Harry Potter/YMMV

Specific Books

 * Philosopher's Stone
 * Chamber of Secrets
 * Prisoner of Azkaban
 * Goblet of Fire
 * Order of the Phoenix
 * Half-Blood Prince
 * Deathly Hallows
 * Fantastic Beasts and Where To Find Them
 * Quidditch Through the Ages

Books In General

 * Accidental Innuendo: There's a whole Facebook page set up for this.
 * Adorkable: Luna, and maybe Neville if you count him as a geek.
 * Alas, Poor Scrappy: When Colin Creevey gets petrified in Chamber Of Secrets, and again when he's  in Deathly Hallows.
 * Alternative Character Interpretation: For nearly every character. Unsurprising given the series' popularity.
 * For instance, is Hermione a Memetic Badass? Mary Sue? Sweet, brainy girl? Insufferable Genius? Despite the fact that Hermione is written as one of the most unchanged characters in the series, she has highly varied fan opinion.
 * There is a good case to be made that Even as of book 7, considering the Worthy Opponent speech Voldemort gives him  but how Neville defied him and pulled the Sword of Gryffindor from the Sorting Hat to kill Nagini . Or that, given Voldemort's paralyzing fear of his own mortality, Neville making Voldemort mortal again could be considered "vanquishing" him as much as, which was really  Rowling has officially debunked this theory, but that doesn't stop some fans.
 * A popular fan theory is that Colin has a crush on Harry, due to the frequent comparisons between him and Ginny in the second book, along with the fact that he's one of the few prominent Gryffindors who never dates anyone.
 * Everything about Snape's morality is debated by fans and let's leave it at that.
 * There are plenty of people convinced that Slughorn is a big ol' pedo.
 * Fan Fiction is divided in portraying Bellatrix as a Broken Bird Woobie or a Depraved Bisexual who is arguably even more sadistic than her canonical counterpart. And then there's Helena Bonham Carter's Psychopathic Womanchild take on the character.
 * Narcissa Malfoy is either a cold, calculating bitch or a woman who genuinely cares for her family's well being.
 * Angst? What Angst?:
 * George loses one of his ears in Deathly Hallows. His first reaction is to make jokes about feeling "holy."
 * Luna Lovegood is all about this trope. She's bullied mercilessly all the time, and she had no friends until recently. Yet she still manages to keep a smiling face in spite of all this, and she keeps the angst inside.
 * Anvilicious: The 'fear of death is bad' message was rather heavy handed.
 * Awesome Ego: Voldemort may be a mass murdering, self-absorbed psychopath but damn is he cool!
 * Base Breaker:
 * Ginny's offscreen development from a Shrinking Violet to a Fiery Redhead, and the development of her relationship with Harry have led to her being one of the most divisive characters in the books, along with her brother Ron.
 * Snape is one of the more extreme examples, and would likely top that list if he were ever paired off with anyone.
 * Broken Base: Pretty much inevitable given how popular the books are. The seventh book's famous/infamous epilogue is just one of example of something the fans can't agree on.
 * Can't Unhear It: Alan Rickman's Snape is so good even J.K. Rowling couldn't unhear it eventually.
 * Cargo Ship: With the general idea of wands and such, it's physically impossible for this not to exist.
 * Complaining About Books You Don't Read:
 * A surprising number of people (perhaps the majority) who have negative criticisms about these books have obviously never read them, for they spout such utter nonsense as the persistent urban myth that the books "encourage children to take an interest in the occult" (contradicted by the opening chapters of the very first book, and reiterated thereafter, such as Filch's attempt to learn magic from a correspondence course).
 * People who label the series as a Cliché Storm couldn't have read the books, or at least not carefully enough. Wherever there's a cliche, Rowling takes it, plays with it, and makes it into her own trope. Dragons? She made up her own breeds and varieties. Prophecies? These take the form of glass balls that can predict anything, no matter how everyday and mundane it is. The Chosen One? Harry was not chosen by fate or by the gods like most fantasy stories. Voldemort marked him as his equal.
 * The noted scholar Harold Bloom can look suspiciously like this at times. In what was neither his first nor last diatribe against the series, he once claimed that whenever a character walked in the series, that Rowling always used the "cliche" of "stretching his legs", and ranted about how Rowling used this "cliche" so often he began taking notes of the number of times people "stretched their legs" in the first book and finally gave up because it was used so often. Fans looked it up...and found the phrase "stretching his legs" was used a grand total of once in the entire series. In Chapter 1 of Book 1.
 * Canon Sue: There are fans who debate and write essays over Ginny, Tonks, or Lily Evans being this.
 * Complete Monster: There's a lot, so it has its own page now.
 * Crazy Awesome:
 * Professor Trelawney smacking down a werewolf with her crystal balls.
 * Dumbledore.
 * Mad-Eye.
 * Bellatrix. Her outright craziness is what makes her Badass, even though she's a shameless Complete Monster.
 * Creepy Awesome: Voldemort and Bellatrix.
 * Death of the Author: Many fans and critics believe that is subject to this trope, since it heavily changes our understanding of the character's motivations without ever being stated in the books.
 * Deconstruction Fic: An absolute avalanche of them.
 * Designated Protagonist Syndrome: Harry, aside from being The Chosen One, has less personality than Ron or Neville,.
 * Die for Our Ship:
 * Ron. And that's if he's lucky.
 * Some of the most chilling examples of DFOS ever have come from rabid and distinguished Harry/Hermione fans who express their desire to have Ginny and Ron locked away, tortured to death, or even spayed/neutered just so they won't.
 * Draco in Leather Pants:
 * Draco, of course, and all the bad guys except Voldemort. Well, he was handsome before his psychosis was set off...
 * Blaise Zabini.
 * While Snape isn't evil, he's still not a nice guy. He knows it. In-Universe, he's described as greasy-haired, with a hooked nose, crooked and yellowed teeth, and a little too skinny to be healthy. And yet, the fans love him. Enough also to ignore all the anti-racism and anti-classism messages in the books and bash Lily Evans for cutting off their friendship when he calls her a mudblood in public and to her face! Rabid Snape fans are terrifying in their attempts to excuse even Snape's worst actions and make him look like a poor victim of destiny, especially when you consider that Snape himself disapproves of his actions in the past and acknowledges it was his own fault that Lily gave up on him. This JF comm has some more details on that.
 * Some people give Bellatrix this treatment. Specially "feminists" who think of her as a "role model" for being a Dark Action Girl Child-Hater.
 * Scabior, due to the pedophilic role that he played in the films.
 * Certain Death Eaters. You'll hardly ever see this with Fenrir Greyback, but Bellatrix and Lucius are among the most common recipients of this trope.
 * Ensemble Darkhorse: As Neville's Badass credentials grew, so did his number of fans.
 * Fred and George, to the point that in many fics bashing the Weasleys, they're usually the only ones who don't seem like Complete Monsters.
 * To say Luna is beloved by the denizens of the internet is putting it mildly.
 * Peter Pullen's portrayal of Yaxley as a classy gangster helped make him one.
 * Scabior.
 * What does it say that fanon!Vernon is a sadistic Complete Monster who enjoys raping Harry, but fanon!Petunia is a guilt-wracked Woobie who deep down wants to be the sweetest, most doting aunt ever? Also applies to Dudley to a lesser extent.
 * Epileptic Trees: Lots of them, especially while the series was still ongoing. This was greatly helped along by Rowling's love of Red Herrings and Chekhov's Armouries, which encouraged many fans to consider seemingly established facts as misleading while considering seemingly unimportant details as important.
 * Everyone Is Jesus in Purgatory: Partially justified, as there's a lot of alchemical symbolism in the series, including characters' names. The problems arise when certain parts of the fandom take the symbols, use them to support their theories, and said theories are entirely wrong. The usual response upon realizing this is to blame Rowling for being wrong, and wistfully talk about how the series would've been better.
 * Evil Is Cool:
 * Bellatrix may be an insane, sadistic monster, but she has one quality that makes the fans love her-she's cool.
 * Even more so for Voldemort himself - he's cool in a creepy and deranged kind of way, but is also an insanely powerful Badass (at least when he's not a disembodied spirit/parasite) with an interesting backstory. There's a reason why characters were hesitant to say his name in the early books.
 * Evil Is Sexy: In the Fandom anyway. It's called "Draco in Leather Pants" for a reason.
 * Pansy Parkinson is pretty cute. In the films, anyway. In the books, she's described as being pretty ugly. She's just mentioned to have a "pug face", actually. And pugs are the epitome of Ugly Cute. So it's reasonable to think she's more frumpy than a Gonk.
 * Sone fans even call Bellatrix a D.E.I.L.F. It's not hard to see why in the movies- Helena Bonham Carter is quite busty, and some of her dresses even show this off, or are combined with Of Corsets Sexy. They usually have a flowy goth look to them, and she wears bright red lipstick.
 * Narcissa Malfoy.
 * Fan Dumb: Given the popularity of the series, too many to count. But here's a partial list anyway.
 * Fandom Rivalry: With Twilight. It can get... heated.
 * Fanon:
 * Fans like to portray Theodore Nott as a Noble Demon among the Slytherin, due to Word of God saying that he sees no reason to hang with Draco and his gang, and therefore might not share the same prejudiced views as his fellow Slytherin.
 * There are two versions of Student McGonagall: Hermione-ish, uptight bookworm or Quidditch--playing prankster. It's also fairly popular to have her as an Auror who fought in the final battle with Grindelwald before she became a teacher.
 * Fashion Victim Villain: Scabior.
 * Foe Yay: Dumbledore and Grindelwald, Harry and Draco, Draco and Hermione. Given the vast quantity of character shippings across the deepest bowels of the internet, every protagonist has likely been paired with every antagonist.
 * Funny Aneurysm Moment:
 * After Ron gets splinched horribly, all of those descriptions that make it sound like a vaguely humorous annoyance earlier in the story aren't so funny anymore. This was lampshaded in the seventh book.
 * It's all too easy to laugh at Neville's constant blunders, not to mention the fact that he lives with a near-tyrannical grandmother. But in the fourth and fifth books, it's revealed what happened to his parents Alice and Frank, and how it affected him. Then it's hard not to feel guilty for having laughed.
 * The use of love potions is Played for Laughs at the beginning of HBP. Then you find out what happened to Tom Riddle Senior, and what later happened to Merope Gaunt because of that, and then you find out the Word of God statement that love potion-conceived children are born without the ability to love. Love Potion was the reason for Voldemort's existence.
 * Hagrid's teary good-bye to Norbert, complete with packing a teddy bear so the dragon doesn't get lonely. Sure, it's funny in the first book, but two books later we learn that was one of the worst days of Hagrid's entire life.
 * Gannon Banned: Electronic Technology is not permissible in any dose at Hogwarts, nor does it work at Hogwarts, period. Claim otherwise on a forum, and you'll come face to face with this trope.
 * Genius Bonus
 * Most of the spells come from Latin (or French, sometimes English).
 * The names of the Blacks: Sirius (the Dog Star), Bellatrix (The Amazon star), Andromeda (the Chained Lady).
 * Many other character names as well.
 * Growing the Beard: Prisoner of Azkaban is usually agreed to be the book where the series begins to take its final shape and where J. K. Rowling really shows her true colors as the genius that she is.
 * Hate Dumb: The early books in particular took a lot of flak in some religious circles for their supposed indoctrination of young people into the occult. (Generally, the arguments were along the lines of Cowboy Bebop at His Computer combined with Complaining About Shows You Don't Watch.) A lot of fury was sparked when a widely-circulated news article reported that J. K. Rowling was delighted that her books had inspired millions of children to worship her lord and master Satan. However, it turned out that the article's source was The Onion. The controversy seems to have mostly dissipated as the release of the rest of the series revealed that Rowling's literary imagery owed less to the occult than to Christian symbolism.
 * He's Just Hiding:
 * Dumbledore.
 * Even Harry thought Sirius Black was hiding behind the veil all the time. The film makes his fate less ambiguous when
 * Parodied in the last book, when Ron tries to think of ways in which
 * Hidden Heart of Gold: In a sense. This would be about the tiniest speck of gold you could find in him, when you realize that Vernon Dursley, whose DNA has been credited to destroy any magic it might come in contact with, married and stayed with Petunia, the sister of a witch. Granted, the woman just about hated magic as much as he did and wanted nothing to do with that world, but she still had a connection to it through Lily even if she didn't have any powers herself. And even after Lily died that connection could've reared its head in any possible way, regardless if they took in Harry. Vernon could have left Petunia any time he wanted and he didn't.
 * Hilarious in Hindsight:
 * The allegations of Satanism were made funny by My Immortal.
 * In the first book, Fred and George bewitch snowballs to bounce off the back of Quirrell's turban. Later, we find out that An already funny scene becomes freaking hilarious.
 * Hype Aversion: Somewhat existed in the late 90s/early 2000s when this series was just beginning to become extremely popular, but by this point, there's barely anyone alive in the civilized world who hasn't seen at least one of the movies or read at least one of the books.
 * Hype Backlash: While most people seem to generally have a high opinion of the books, there will always be a small minority who believe the books to be overrated and that they've read better. When a series is described as "an instant classic" or "the finest of modern literature", they're blatantly setting up a target for a cynic to potshot at.
 * Iron Woobie:
 * Harry gets beaten, captured, and/or tortured in every single book. And this is nothing to the ten years of nonstop neglect and dislike the Dursleys gave him prior to him becoming a wizard.
 * Neville. While Harry's parents are dead, Neville's, which is, in a way, worse.
 * And while Neville has always had the support of friends to keep him going, Luna only ever had the company of her father after her mother died. She's bullied as bad as Neville is due to her eccentric personality, and she didn't have friends until she met Ginny and later Harry, Ron, Hermione and Neville. And yet, she always manages to be cheerful and enthusiastic in the face of this misery, even though it bothers her more than she lets on. Much more.
 * It Was His Sled: In book 6, Snape killing Dumbledore.
 * Jerkass Woobie: If you had a quarter for every time a character who initially appeared to be just a straight-up asshole actually was a good person deep down, or how often a woobie turned venomous, you could conceivably rival Rowling's fortune.
 * By the fourth book, Harry has plenty of legitimate reasons to be upset. However, he takes it out on others more than is really good for him. (Although it might be controversial to label him and Ron as such)
 * Draco Malfoy in books 6 and 7.
 * Snape might as well be the trope incarnate. He was abused by his parents and bullied by his peers, but LOTS of his suffering is due to his own actions. And this doesn't even touch on.
 * Barty Crouch Sr., mostly in the films.
 * Love to Hate:
 * Stephen King said that the strength of a story relies on the strength of its villain. Umbridge, he said, is the best villain since Hannibal Lecter.
 * Voldemort.
 * The Malfoys.
 * Magnificent Bastard:
 * Barty Crouch Jr. He's notably the only character in the story to have completely outwitted Albus Dumbledore, though Dumbledore caught up with him in the end.
 * Maybe Voldemort. He IS a genius, and a good strategist, though his plans seem complicated, they work until the end when Harry is lucky again so people really should stop criticizing them so much. His plans rely on him anticipating his opponents moves and moving pieces around, which he does pretty well. Especially his brilliant takeover of the ministry of magic and the wizarding world where he eliminated strong members of the ministry and took control of Scrimgeor's closest advisors and friends, and his use of his invention, the Taboo curse, to track all remaining order members. Imagine if Harry never existed. Voldemort may very well be ruling the world, since everyone else, except Dumbledore, poses absolutely no threat to him. He completely destroyed the Order, and though there was resistance, we all know it just kept crumbling. But he ultimately ends up as a Smug Snake due to delusions of grandeur and his descent into absolute madness.
 * Dumbledore. Directly and indirectly, intentionally and otherwise, this one man, in some way or the other has been responsible for everything, everything, that has driven the history of the Potterverse from his time on and even beyond. Sure, he's the good guy, but then he fits all the characteristic tropes to a T, only with certain limits in the present that's more along the lines of a Guile Hero.
 * Memetic Badass:
 * Neville would have done it in four books. Five, max.
 * His patronus is Chuck Norris.
 * In meta, Dumbledore is responsible for the lines "WHAT THE HELL ARE YOU DOING YOU MOTHERFUKERS!" and "Harry, you must rock the fuck out."
 * Memetic Molester:
 * Fenrir Greyback.
 * Scabior, who takes up Fenrir's sexual overtones in The Movie.
 * Memetic Mutation:
 * Scabior's plaid pants.
 * The fact that characters don't say Voldemort's name has gotten people to refer to things they don't like as He/She/It who/which must not be named.
 * A "Flint" came to mean a factual mistake Rowling has made in her writing: He's still at Hogwarts in the third book even though he should have left at the end of the second. When asked about this, JKR said that either she'd made a mistake or he'd had to repeat his last year, and that she preferred the latter.
 * "NOT MY DAUGHTER, YOU BITCH!"
 * Misaimed Fandom: Boy howdy...
 * Helena Bonham Carter has noted that many fans are revolted by Bellatrix, yet partially want to be her.
 * Lucius Malfoy has many fans, including his own actor.
 * Moe:
 * Gabrielle Delacour.
 * Luna, due to being The Pollyanna.
 * Neville, due to being The Woobie.
 * Even Tonks' Dojikko attributes can be considered Moe attributes.
 * Moral Event Horizon:
 * Snape seems to cross this when he
 * Some would argue that Voldemort was evil from birth and that he was born on the Horizon. Others would say that it was crossed when he tortured the children in the cave as a boy, or when he killed somebody's rabbit, or when he made his first Horcrux. Or, y'know, killing Harry's parents and then trying to kill the infant Harry.
 * Five possible ones for Bellatrix: When she, her husband, her brother-in-law, and Barty Jr. subject Neville's parents Frank and Alice to a Fate Worse Than Death: prolonged torture by the cruciatus curse, causing them to become insane, unrecognizable vegetables. It's even worse when you consider that they did it when Voldemort was gone.
 * Mocking Molly Weasley for freaking out after
 * While Barty Jr. joined the Death Eaters due to neglectful parenting, there's still the fact that he willingly took part in Bellatrix's Moral Event Horizon, Alice and Frank's incurable insanity is on his head as much as Bellatrix's.
 * For Lucius Malfoy,
 * Uncle Vernon spends a long time hovering towards it, but finally crosses it when he kicks Harry out of his home, knowing full well that this will likely lead to his death at Voldemort's hands. But by the end, he seems to have developed a grudging respect for Harry. This is averted in the film version, he just simply locks him in his room.
 * Order of the Phoenix has Dolores Umbridge cross this when she or when she pulls out the Blood Quill.
 * Never Live It Down: The whole "Ginny is a slut" meme, despite her having only dated three men in her entire life. Each relationship lasting more or less a year. Made worse by how it not only involves slutshaming, but also Die for Our Ship. As well as a good deal of hypocrisy, considering that Hermione also had more than one beau aside of Ginny's brother Ron, but she's not slutshamed for it.
 * Nightmare Fuel: An entire page of it!
 * No Such Thing as Bad Publicity: In real life, Harry Potter got publicity just for being banned in some places for promoting witchcraft.
 * Older Than They Think: The success of Harry Potter led some publishing houses to issue re-prints of already existing books about kids with magical powers. Many people thought that these books were riding on the coattails of and/or "ripping off" Harry Potter, when rather these books were years (or decades) older than the first Harry Potter book. Some people who had never read a fantasy novel before Harry Potter think that the series is actually the Trope Maker for many of the tropes contained in the books. Though, the series was the Trope Codifier of many of the already-made tropes, so people can hardly be blamed for not being as well-read in obscure works as Rowling was.
 * Some particular examples include Wizard's Hall and The Legend of Rah and the Muggles, two books published before Rowling's time; Wizard's Halls writer has heavily implied (though never outright stated) in interviews that she thinks Rowling plagiarized her, while The Legend of Rah and the Muggless writer outright claims plagiarism and tried to sue Rowling.
 * The beginning of the series and many characters bear a resemblance to The Worst Witch. Just look at this fanpage from 2003.
 * One True Threesome: Harry, Ron and Hermione, of course.
 * Real Women Never Wear Dresses: Many people bash Molly for being a Housewife, and  And there's the slutshaming and bitchiness that the fangirls apply to Ginny for "not being enough of a rolemodel" and "stealing Harry 'from the more deserving and stronger' Hermione" Because it's sooooo feminist to say Hermione's happiness won't mean anything if she doesn't have Harry as her prize cock!
 * Rescued From the Scrappy Heap:
 * Fleur Delacour becomes much more sympathetic after Harry  And especially in Half Blood Prince, when it's revealed that she's not as shallow as she seems and fully intends to marry Bill despite his disfigurement (it's even this in-universe for her future mother-in-law).
 * A few regard  as this.
 * Ron the Death Eater: Ron, the Weasleys, and pretty much all of the good guys. But by far, Ron and the Weasleys are afflicted with this, except for Fred and George.
 * Cho Chang suffers from this a lot within the fandom, turning a very troubled young girl into a crazy, jealous bitch.
 * While Snape's far from flawless, there are those who will completely overlook his desire to protect people and his loyalty to Dumbledore. There are also those who will say that preemptive karma justifies James and Sirius bullying him at school.
 * On the other hand, rabid and crazy Snape fans insist that James and Sirius are Complete Monsters and that James bullied/raped/forced Lily into marry him instead of the fanon!Snape they have in mind. Not to mention there's how they demonize Lily for not taking Snape's own bullcrap, openly saying she was a bad friend and a total whore for cutting her friendship with him when she had all the reason in the world.
 * The entire wizarding world gets this pretty bad. If you listened to the wizard haters talked you'd think wizards were a bunch of bloodthirsty, useless, genocidal retards. It gets even worse whenever you take into account that they clearly don't know the text, such as how wizards have had alliances with people in other countries since the Middle Ages, which is way ahead of Muggles, or that there seems to be almost perfect equality between the sexes, or that Word of God confirms that wizards are somewhat less homophobic, or for that matter using the rubber duck line from the second MOVIE to show how retarded they think wizards are. It gets even worse with recent information from Pottermore, when Rowling's notes state that even in the 1600's whenever Muggles were just beginning to get over their Burn the Witch hysteria the wizarding public still rebelled against authority because their leaders were too cruel to Muggles, or that during the World Wars the wizards broke the law to help the Muggles they supposedly hate, or the fact that it heavily implies wizards never had a Colonial era.
 * Rooting for the Empire: Loads of it among the fandom; instances range from relatively sane (wishing there were more good Slytherins) to completely and utterly ca-ca (woobifying Umbridge).
 * The Scrappy: Dobby. This is a glaring instance of Misaimed Fandom considering how Dobby is such an Iron Woobie.
 * Ship-to-Ship Combat: Many Remus/Sirius fans have Nymphadora Tonks as a Relationship Sue who caused JK Rowling to ruin a perfectly good gay character.
 * Spoiled by the Format:
 * Averted by the writer in that Rowling actually did a pretty good job of making sure that big events happened on the beginning of the next turned page, rather than on the right side where you could notice it as you read down the left.
 * Played straight for Savvy American readers did their best to ignore Mary Granpre's illustrations at the beginning of each chapter, as sometimes it wasn't hard to figure out plot points from them.
 * Also played straight in Deathly Hallows
 * Also played straight in Half Blood Prince if 1) on the night of the book's release, one happened to glance at the Table of Contents because one was curious as to how long the book was going to be, since Rowling had said it wasn't going to be as long as Order of the Phoenix, 2) one then saw before they could look away that the final chapter was called, "The White Tomb", and 3) one had read enough books about Harry Potter and its sources and inspirations to know that "Albus" is Latin for "White". Why the combination of all 3 could cause a fan to curse aloud in frustration, since before reading a single word of the story, they now already knew who was going to die in Book 6 (even if they didn't know who kills him).
 * Squick: Several scenes imply Umbridge has a crush on Fudge, though it's likely she'd show similar signs of affection for any reigning minister.
 * Strangled by the Red String: In some peoples' viewpoints, Harry and Ginny. See Broken Base.
 * Tear Jerker: Many, actually. See the page.
 * They Wasted a Perfectly Good Plot: A Lot of people were hoping that Neville would get to avenge his parents in a fight against Bellatrix.
 * Too Cool to Live:
 * Unfortunate Implications:
 * The only canonically gay love is also the only time in the series when the The Power of Love -- as opposed to an infatuation like Merope's -- is a destructive force. In a series about how The Power of Love is the most powerful magic of all. His attraction also led him down a path of severe prejudice and attempts for world domination. Part of becoming The Atoner was leading him a celibate life.
 * Also, the house elves are happy to serve wizards, with the exception of Dobby, . They like to serve, but they don't like the abuse. They are still, however, completely devoted to their masters (with a few exceptions). Dumbledore, though, warns that if wizards don't start treating house elves as their equals, they'll wind up paying for it.
 * There's even a possible subtle Take That, Critics! in there, with SPEW. Hermione's assumes she knows what's right for the House Elves despite the wishes of the Elves themselves, which is itself an Aesop about her mindset. Almost as if Rowling anticipated the reaction to the Happiness in Slavery bit.
 * House elves seem incable of existing without a master. Species don't just exist like that. There are symbiotes and parasites but not slaves who will simply take the abuse from their masters without leaving not to mention the weird rules they follow. They even require a possession of their master given to them? Combined with the fact that only richer families seem to have them and regular humans certainly don't have them it comes across as if some rich and influential wizards enslaved them in the past for their own personal use.
 * Of course this is ignoring all the fact that the seventh book finally shows Hermione to be right. Whenever Kreacher is bashing his head into the ground for being physically incapable of following Regulus's order the narrator says that Harry finally understood Hermione's POV.
 * It is indicated, based on the Black Family Tree, that virtually every Pureblood family is related in some way through intermarriage. Now bear in mind that a large proportion of this group only marries other Purebloods. Please consider the implications, and just how unfortunate they are.
 * To really hammer in the point, if you look at the family trees of some of the pure blood characters, you'll realise something incredibly creepy; almost every single pure blood family is related to the Black family, either by blood or by marriage. This makes all of them distantly related - for example, it's likely that Neville, Ron and Barty Crouch Jr (of all people) share the same great-grandparents. This all makes some of the marriages that take place very dodgy - since the Potters were related to the Blacks, and the Weasley family were as well, it could be possibly that Harry and Ginny are very distantly related. Google Image the family tree for yourself, and the unfortunate implications really will start booting you in the face.
 * Compare the goblins in Harry Potter with the stereotypical medieval European image of Jews. The implications, they are unfortunate.
 * What about the way that Rowling treats Muggles in general? Despite the fact that a large portion of the series is dedicated to showing how pointless racism against Muggleborns is, all the Muggles present in the books are either rude, stupid, or just generally incompetent compared to the wizards. Then there's the fact that the idea of being a Muggle or a Squib basically amounts to "Oh, so you're non magical? Too bad for you!"
 * The Minister of Magic thinks an acceptable amount of "communication" with the Prime Minister is showing up in his office every once in a while to tell him about important stuff. Aurors mindwipe witnesses and cover public incidents up as catastrophic accidents. And we see what happens with a Muggle investigation into a magical murder (the Riddles): nothing. An SAS/Auror taskforce would make out like gangbusters, if the Wizarding World got over their patronizing attitude to Muggles long enough to form one. For Pete's sake, they think telling only the Prime Minister about magical terrorist attacks is good practice.
 * It's Played for Laughs when a wizard spends a good deal of time altering a Muggle's memories of wizards showing up to watch the Quidditch World Cup, apparently without anyone considering how casually he's erasing a person's memories.
 * Of course you're all ignoring that the Muggle world be tossed into chaos by revealing magic, or how superstitious people were until wizards started hiding themselves. Also, you're all acting like wizards just sit by and allow all the crime to happen.
 * Hermione jinxes the DA signup sheet so anyone who betrays them gets "SNEAK" written across their face in pimples. Marietta betrays them, but only after pressure from her mother and Umbridge, and it happens to her. Even after the pimples fail, she's left with the marks. Rowling's word on the matter is "I loathe a traitor." These are teenagers in school, not professional soldiers. It's a wonder one of them didn't crack sooner, and they can't really be blamed if they did. If they are at fault, they don't deserve disfigurement, especially since Hermione didn't actually tell anyone about the jinx. Now, if she had jinxed it to tell her they had been betrayed, and by who, that would make more sense.
 * Furthermore, Hermione's jinx bears a very creepy resemblence to the medieval punishment of branding a convicted person's crime on their face so that all could see it on them for the rest of their lives. Rowling's insistence on making it permanent and her "I loathe a traitor" comment make it sound like she heartily approves of this kind of inhumane punishment.
 * Unpopular Popular Character: Luna.
 * Villain Decay: Some argue that Voldemort was scarier before he started Putting on the Reich.
 * Wangst: Harry's behavior is the later books is considered this by some. Of course, he's a teenager. With many, many horrible problems on his hands.
 * What Do You Mean It's Not Political?:
 * Many people are convinced that Voldemort represents George W. Bush. Alfonso Cuaron (director of the film version of Prisoner of Azkaban) said that he envisioned Big Daddy V as a combination of Bush and Saddam Hussein. Rowling said he's the worst traits of Adolf Hitler and Josef Stalin combined.
 * The Death Eaters were an update of Those Wacky Nazis. Of course, in the fourth movie, they look like gothic KKK ripoffs. The ministery police officers in the 7th movie actually LOOK like Nazi officers, what with the uniforms, hats, and armbands.
 * Fudge is Neville Chamberlain; Dumbledore is Winston Churchill.
 * Some say Umbridge and/or Bellatrix remind them of Sarah Palin. Which doesn't make a lot of sense since the books were written before Sarah Palin rose to prominence.
 * Aunt Marge and Umbridge could be seen as expies of Margaret Thatcher, whom Rowling had a hatred for.
 * Grindelwald gets a lot of Hitler comparisons -- pureblood supremacy, powerful in the early 1940s, German...and defeated in 1945 by a British to boot. What Do You Mean Its Not Symbolic indeed. This one is more than just fan speculation -- Rowling has strongly hinted in interviews that Grindelwald was involved with the Nazis (specifically, she said that the fact that he was brought down in 1945 was "not a coincidence").
 * The Woobie:
 * Moaning Myrtle, Remus Lupin, and probably more.
 * Draco Malfoy when he becomes a Jerkass Woobie in Books 6-7, especially considering that when he's under the most pressure in Book Six, he cries on  shoulder.
 * Luna. Even the emotionally-inept Harry is described as feeling a combination of embarrassment and pity at her good nature and cheer in the face of having no friends and being relentlessly teased.
 * Merope Gaunt is pretty much the most pathetic character in the whole series. Considering what we do see of her life, was it really a shock that, she simply lost her will to live and just died?
 * Neville can't catch a break. Rowling has it out for him - not only because of what happened to, but the fact that in class, all magical backlashes direct back to him.
 * Dobby. "Dobby is used to death threats, sir. Dobby gets them five times a day at home."
 * Cho Chang. Several fanfic writers feel no sympathy for her, but it's hard not to feel sorry for her about her emotional stress after Goblet of Fire. And even aside from that, the fact that she's continously dumped on by fans and even the narrative of the books (especially when it's in favor of Ginny) earns her some sympathy points.
 * Ron is picked on by his big brothers, grows up in poverty, gets taunted mercilessly by the local bullies, constantly overshadowed by both his best friends, endures being a more or less constant Butt Monkey... and that's a very brief summary of what he goes through.
 * Ginny Weasley in Chamber Of Secrets.
 * Peter Pettigrew . It's easy to feel bad for poor, weak, picked-on Peter..
 * The exact same thing could be said for "P-poor, st-stuttering P-Professor Quirrel."
 * Sirius Black.
 * Hagrid never saw his mother, he lost his dad at a young age, he was framed for something he didn't do and then he had to watch all his fellow students grow up over the years and become wizards while he tended to the grounds. It's easy to see why such an outwardly tough character is sentimental on the inside.
 * Kreacher. Poor, poor Kreacher. Lampshaded in the seventh book when it's said that the only thing he ever wanted was someone who treated him lovingly. That only person was, and Kreacher had to watch the man die in the cave. You can't help but grill Sirius for his poor treatment of the elf. A real Crowning Moment of Heartwarming is when he is presented the fake locket, and he becomes much happier and polite afterwards.
 * The dragon in Gringotts. It spent all its life without fresh air or humane treatment, forced to guard bank vaults. On top of it all, the goblins taught it to associate the sound of clanking metal with intense pain. Specifically, being stabbed with red-hot swords. A miniature Crowning Moment of Heartwarming is when it takes off into the horizon, able to start a new, proper life. It was the right thing for Hermione to be sentimental about the poor creature. The film illustrated this wonderfully by having the dragon pause to breathe in the blissful fresh air before taking off.
 * Woobie Species: House-elves.
 * Kreacher. Poor, poor Kreacher. Lampshaded in the seventh book when it's said that the only thing he ever wanted was someone who treated him lovingly. That only person was, and Kreacher had to watch the man die in the cave. You can't help but grill Sirius for his poor treatment of the elf. A real Crowning Moment of Heartwarming is when he is presented the fake locket, and he becomes much happier and polite afterwards.
 * The dragon in Gringotts. It spent all its life without fresh air or humane treatment, forced to guard bank vaults. On top of it all, the goblins taught it to associate the sound of clanking metal with intense pain. Specifically, being stabbed with red-hot swords. A miniature Crowning Moment of Heartwarming is when it takes off into the horizon, able to start a new, proper life. It was the right thing for Hermione to be sentimental about the poor creature. The film illustrated this wonderfully by having the dragon pause to breathe in the blissful fresh air before taking off.
 * Woobie Species: House-elves.

Films
"Harry: Ron! What is it? Ron: (whimpering) Spiders... asking me to tap-dance... but I keep telling 'em I don't want to! Harry: (forcing back a laugh) Well you tell 'em you don't want to! Ron: (spaced) Yeah... (collapses immediately on the bed)"
 * Adorkable:
 * Harry and Hermione's dancing in Deathly Hallows: Part 1.
 * Neville teaching himself to dance in Goblet of Fire, being completely unafraid of looking like a twat or a nerd, like a lot of boys his age would be. So cute, it almost goes into Crowning Moment of Heartwarming or Squee territory.
 * And the Fandom Rejoiced:
 * Evanna Lynch is Luna Lovegood!
 * The Tale of the Three Brothers told in a beautifully animated sequence.
 * Alan Rickman is one of the least contested casting choices, with the main complaint being that he's so much older than Snape.
 * As soon as you see her, it's hard to imagine anyone but Maggie Smith playing McGonagall.
 * Bill Nighy is Rufus Scrimgeour!
 * Award Snub: The series didn't win a single Academy Award during its 10 years.
 * Awesome Music: Courtesy of John Williams above all; the music by the replacement composers is generally well-liked, too. The best can be found here.
 * Better on DVD: While the movies don't make complete sense on their own, they make better sense when viewed in a marathon (esp. with the deleted scenes), especially since the installments are released one or two years apart, which adds up quite quickly. It's a bit much to expect someone who didn't rewatch the series on DVD to remember Gryffindor's sword after eight years.
 * Big Lipped Alligator Moment:
 * In Prisoner of Azkaban, there's-
 * The talking shrunken head on the Knight Bus.
 * The choir singing the witches poem from Macbeth.
 * Once in Griffyindor's Boy's Room in the middle of the night, Ron bolts up, shaking and whimpering something incoherently.


 * In Goblet of Fire, the students from Beauxbatons and Durmstrang introduce themselves with dance. It's even worse in the deleted scene, where the Hogwarts students responded by singing their school song. The Durmstrang and Beauxbatons students look reasonably uncomfortable.
 * In Half Blood Prince, the Death Eaters destroying the Burrow. The kids just go back to school and the Burrow's just fine in the next movie.
 * Harry and Hermione's dancing in Deathly Hallows Part 1. Whether you find the scene touching or hilarious, it still came out of nowhere.
 * Giant spiders suddenly attacking in the final battle of the final film. This was in the book, and it made only slightly more sense there.
 * Continuity Lock Out: Because of time constraints, much of the backstory gets cut, leaving many viewers who haven't read the books scratching their heads: each individual movie is more or less comprehensible by itself, but when put into a movie continuity, certain things don't make sense.
 * In the third film, the simple fact that Sirius is innocent and was framed by Pettigrew is explained in the most confusing manner possible. This sentence probably just explained it more clearly than any line in the entire movie.
 * They also cut out Dumbledore's argument with Cornelius Fudge, which greatly foreshadowed the events of The Order of the Phoenix.
 * Prisoner of Azkaban never explains who Moony, Wormtail, Padfoot and Prongs are. Then, Harry calls Pettigrew "Wormtail" in the Goblet of Fire movie without explanation, and Sirius is called "Padfoot" in OotP.
 * Neither an explanation for how Lupin instantly recognizes the Marauder's Map for what it is nor for how Sirius knows that "The Map never lies" is given as well.
 * In Goblet of Fire, the corpse of Barty Crouch Sr. is removed from the woods… only for him and his death to never be mentioned again. (Not even when the assassin reveals himself.)
 * 's back story is changed from "believed to be dead" to "still imprisoned in Azkaban". This may be very confusing for moviegoers, who are now expected to believe he could have escaped with nobody noticing while the plot previous film revolved around another escape that was discovered instantly.
 * The plot and tension of Order of the Phoenix hinge on the fact that the only person who will admit to Voldemort's return is Harry Potter. The problem is that if you saw Goblet of Fire, you know that isn't true. Because the Ministry of Magic clearly has someone in custody who could tell them (or they could magic it out of his head):, who is last seen alive and being taken into custody at the end of the film. Of course, the book of Goblet of Fire had him kinda-killed off. This is not done in the film, and thus you need to read the books in order for the continuity of the films to make sense.
 * Percy is given only a cameo with no explanation as to why he's on the Ministry's side, nor why he's.
 * The entire point of Snape's flashback during Occlumency, which was was not in the final cut. It was the massive turning point for his character. They were apparently forced to cut it out due to Executive Meddling, but the problem remains the same.
 * Because the potion book subplot of Half-Blood Prince was so shortened, The Reveal that makes very little sense. It's clear that this is why the book let Harry be so good at Potions, but even that is minor.
 * It also left out what may be the single most important minor detail in the story. Specifically, Harry puts on the stone bust of an ugly wizard in the room of requirement. This turns out to be . In Deathly Hallows, Part 2, the writers handwaved it by.
 * The movie also fails to point out that since it left out the bits where Harry and Dumbledore
 * This trope is actually Inverted between Half-Blood Prince and Deathly Hallows Part 1 - a Big Lipped Alligator Moment halfway through Half-Blood Prince that wasn't in the book involves the bad guys burning The Burrow (the Weasleys' house) to the ground. With no explanation at all, it reappears without a scratch in Deathly Hallows.
 * Deathly Hallows Part One does not waste one second bringing people up to speed on who the characters are or what they're doing. Movie critics have not let this pass without comment.
 * It also relies heavily on a shard of that Sirius gave Harry in OotP as a visual and plot device - despite the fact that it did not appear in the OotP movie. Turns out in Part 2 that . But we don't know how it ended broken, or in Harry's hands. It seems highly probable that this was in the original cut of Order of the Phoenix, but thanks to Executive Meddling, it was cut for the theatrical version.
 * Creator's Pet: Hermione, to a lot of people. She is known to be the screenwriter's favorite character. While in the first two films she was portrayed utterly correct to her role in the books, the third film prettied her up considerably (though this may have just been how the actress grew up), gave her most of Ron's better lines, had her wear pink, and generally portrayed her to be the leader of the Trio who could do no wrong. The fourth film, too, calls a lot of attention to how beautiful she apparently is. By the last film, this is toned down considerably (Ron actually figures out two important plot points before she does, for instance).

"Tom Felton: "...Even with those teeth, I'd still... you know.""
 * Draco in Leather Pants: Barty Crouch, Jr. Thank you, David Tennant.
 * Freud Was Right:
 * Cormac MacLaggen's deluxe-model broom, as compared to Ron's smaller thinner hand-me-down one in Half-Blood Prince.
 * When Voldemort takes Lucius's wand in Deathly Hallows (snapping off its cane handle), Lucius flinches as if he had just been castrated.
 * He decapitated poor Snakey!
 * Ensemble Darkhorse: Quite a few characters not given much attention in the books suddenly become more popular once there's an actor playing them. One example? Yaxley, who in the books was just a named Death Eater. In Deathly Hallows Part 1, he acts more like a well-dressed British gangster. It helps that he's played by the badass Peter Mullan. Also, his walking instead of running after the fleeing Trio in the Ministry made him a lot scarier!
 * Evil Is Sexy: Bellatrix Lestrange. In the books, her stay in Azkaban had strongly diminished her beauty. In the movies, however...
 * Her teeth are really manky and disgusting, though. Then again...


 * Barty Crouch Jr.
 * Scabior.
 * Lucius Malfoy.
 * Everybody Remembers the Stripper: The frequently asked topic of conversation in most press interviews for Deathly Hallows Part 1 was the filming of the Horcrux visions of topless Harry and Hermione kissing.
 * Fountain of Memes: Deathly Hallows, Part 2. Hundreds, if not thousands, of Facebook pages sprang up over night. "Boom?", Neville's cardigan, Voldemort's NYEAH, hugging Draco...
 * Growing the Beard:
 * Definitely debatable, but Prisoner of Azkaban and Goblet of Fire were the best reviewed movies in the series, so this applies for critics. It was with Prisoner of Azkaban that the series became a more Pragmatic Adaptation.
 * Deathly Hallows Part 2 appears to be the most universally-approved adaptation - critics loved it, and the fanbase is largely positive towards the overall product (though not without the occasional quibble). Given that Part 1's reception was a little more lukewarm and rather more divided, this is especially impressive.
 * Hate Dumb:
 * We all knew Sir Michael Gambon was never going to top Richard Harris as Dumbledore, but some of the hate he got for it is really scary.
 * Let's not forget Katie Leung aka Cho Chang getting lots of fangirl hate, death threats included.
 * Harsher in Hindsight:
 * The sixth film suddenly just got a lot less funny due to  in the last film.
 * A more long-term one: all of Neville Longbottom's Butt Monkey moments become this as his childhood traumas are eventually revealed. In particular, Goblet of Fire, fainting during Mad-Eye Moody's Crucio demonstration, when the Pensieve scene later reveals that that was what happened to his parents.
 * Hilarious in Hindsight:
 * Cedric Diggory makes his entrance jumping out of a tree. Maybe he was bothered.
 * Furthermore, Harry's incredibly handsome fangirl magnet of a rival is played by Edward Cullen's actor!
 * After Bill gets mauled by Greyback, the narration states that he "now bore a distinct resemblance to Mad-Eye Moody. Moody is played by Brendan Gleeson. Bill is played by his son Domhnall.
 * One reason to never take  seriously ever again: A Very Potter Musical. Seriously, try watching it without thinking "YOU'RE SUCH A SPARE!!!". At the same time, Voldemort's resurrection will never be scary again because of that damn musical. "TO DANCE AGAAAAAAAAIIIINNN!!!!!!
 * Ho Yay:
 * In Deathly Hallows, the book, Malfoy intentionally stays far away from Harry at Malfoy Manor and doesn't look at him directly because he's afraid of what will happen if he identifies him. In the movie, he comes very close, kneels down to Harry's level, and stares deep into his eyes for a long moment....
 * The movie of Deathly Hallows actually downplays a (possibly one-sided) gay relationship present in the book between Grindelwald and Dumbledore, rendering it no more than Ho Yay.


 * Internet Backdraft: Want to have some fun? Find some Potter fans and claim you prefer the films to the books. Expect them to retort that that is because you haven't read the books. And then, if you really want to have some fun, say you have read the books and still prefer the films.
 * It's the Same, Now It Sucks: The film series' fanbase's opinion, especially if they prefer the later films to the first two. See also They Changed It, Now It Sucks, below.
 * Memetic Mutation:
 * "Dobby never meant to kill! Only maim, or severely injure!" is quickly picking up steam.
 * "Turn to page 394." It's due mostly to Snape fangirls finding Alan Rickman's delivery of this very random line extremely sexy. The fact that he repeats "page 394" a couple times later in the scene pushed it to full-blown meme status.
 * In less than a day, Voldemort's scream of "NYEAAHHHHH!" found in the trailer for Deathly Hallows Part 2, mainly because the exact same scream is repeated four times throughout the trailer, with the result that it becomes rather... amusing.
 * The pimp cane.
 * Voldemort and Draco's incredibly awkward hug in Deathly Hallows Part 2. Along with his awkward laughter.
 * Edward fears Voldemort.
 * Memetic Outfit: Hermione's pink hooded sweater in the third film.
 * Moe: Gabrielle Delacour is tiny and cute and French. Luna Lovegood (Evanna Lynch) is so cute, and so much The Woobie, that you just want to give her a hug and some soup and tell her it will all be better tomorrow.
 * Moral Event Horizon: In Chamber of Secrets, Lucius was clearly about to cast Avada Kedavra on Harry, as opposed to the book version where his spell is ambiguous. He's about to kill a 12-year old, over a house elf! This is really Jason Isaac's fault - he was told to just use "a spell", and the first thing that came to mind was the words of the Killing Curse. He later admitted that he hadn't realised which spell he'd been wording until after filming was completed.
 * Periphery Demographic: Hermione and the actress who portrays her, Emma Watson, are really popular among male fans.
 * Rescued From the Scrappy Heap: Many reviewers and fans feel that Dobby's appearance in Deathly Hallows, Part 1 significantly improves his character.
 * Retroactive Recognition: OMG ITS EDWARD!!!!!!
 * Ship Tease: The end of the last movie shows a single, silent scene where Luna joins Neville resting in the Great Hall after the last battle. This scene doesn't have much purpose other than to be a Ship Tease. This could also be an example of Pair the Spares.
 * Smurfette Breakout: Out of the three leading actors, Emma Watson has received the most publicity. While Daniel Radcliffe and Rupert Grint have gotten a large amount of roles, it is Emma who has remained in the public eye the most.
 * Special Effect Failure:
 * The "19 years later" epilogue in Deathly Hallows, Part 2 appears to attempt to make the actors (who are as much in their early-to-mid 20's) look like they're in their late thirties solely by putting them in big coats. It's hilariously awkward.
 * The first film is somewhat infamous for its obvious Chroma Key composites and quickly dated CGI. Chris Columbus has spoken about this in interviews and indicated that he made a deliberate effort to do better on the second film. His mistake on the first movie was shooting all the effects scenes towards the end of the shooting schedule, giving the effects people only a few months to complete their work. On the second movie, Columbus shot the effects scenes at the beginning of the shooting schedule, giving them a whole year instead.
 * Lily and James' gravestone in Godrics Hollow finally confirms that the films are following the same timeline as the books (in spite of the whole Millenium Bridge incident). Then in Snape's flashback scenes the make-up artists/visual effects team apparantly decided not to help out 64-year-old Alan Rickman in his portrayal of a 21-year-old man. The same goes for Lily and James' actors looking in their forties in the same scenes.
 * Tainted by the Preview: On August 14, 2008, Warner Bros. announced to push Half-Blood Prince's intended November 21, 2008 release date to July 15, 2009 due to the Writers' Guild of America strike of 2007-2008, despite releasing a teaser trailer for the film a month earlier. This caused so many angry outbursts from hundreds of Harry Potter fans, who called for boycotts of the studio and their products, and sent numbers of nasty hate-mail to the studio. After that, Warner Bros. responded to these outraged fans by sending an apology letter, which promptly ended with "We love the fans". But the fans think this letter is an insult and continue to boycott the studio.
 * They Changed It, Now It Sucks: The film series' fanbase's opinion, especially if they preferred the first two films to the later films. See also It's the Same, Now It Sucks, above.
 * The Woobie: The list of Woobies in the movies pretty much correspond to the one in the book version. However, Professor Trelawney gets Woobie status in Order of the Phoenix in the scene where she's fired by Delores Umbridge and forced to leave Hogwarts with her bags in front of the whole school. Emma Thompson's heartbreaking performance makes it an absolute Tear Jerker in the movie.

Video Games

 * Big Lipped Alligator Moment: The side missions in Deathly Hallows Part 1. For example, Harry is searching Grimmauld Place... Suddenly, he finds himself in a dragon's cave!
 * Ear Worm: The first few games were scored by Jeremy Soule, so it's a given.
 * Excuse Plot: Gameplay takes precedence over Rowling's complicated plots, so the storyline of each book/film is more-or-less reduced to this for the game. But let's face it -- practically everyone who plays these games knows the plot already anyway.
 * Hell Is That Noise: Chamber of Secrets has multiple examples, but the most notorious are the ghost enemies, who always make an eerie wailing sound right before they attack Harry. It's a creepy enough noise to listen to if the ghost is in front of you and you can at least see it preparing to attack. If the ghost happens to be behind you or on the other side of a wall, and you don't know until that horrible sound suddenly comes out of nowhere....
 * It's Short, So It Sucks: The games based on the 7th/8th movie(s). Angry Joe even pointed out he finished Part 2 in 2:52, which is just 20 minutes longer than the film's running time.
 * Narm: Lots of it: Hermione's voice acting in the fifth game. Her voice actress who had played her for the past few games had been great, but for this game, she was quite wooden, and constantly stated the obvious.
 * The Problem with Licensed Games: The first 4 games kinda averted it. The others, not so much.
 * They Just Didn't Care:
 * Half-Blood Prince doesn't bother introducing Romilda Vane, Harry's fangirl. However, Harry still gets her love potion spiked cauldrons, which Ron eats. Then you have to brew the goddamn cure.
 * Worse than that, you find Polyjuice Potion instructions (and naturally have to brew the potion to find out what it is) even though the Polyjuice subplot is eliminated from the game as it was from the movie. So the game makes it a huge plot point that Draco Malfoy is brewing Polyjuice Potion for some mysterious purpose, but then never explains what it's for.
 * The first game never explains who Voldemort is, apparently figuring that simply saying "Harry Potter... The Boy Who Lived" magically covers the whole Backstory. Made all the more egregious by the fact that the intro movie then spends an inexplicably long time detailing the scene in which Harry asks the Sorting Hat not to put him in Slytherin.
 * The PC version of Chamber has Dobby warn Harry not to go to Hogwarts, and then he disappears. He doesn't cause the Dursleys to lock Harry up and he never appears again. In short, his appearance is never explained and has no impact on the plot. He's just there because the book/movie says he's supposed to be.
 * In the first game, the teachers award you house points for how well you learn spells. One spell, however, is taught to you by Hermione... so she randomly awards you house points! And she insists while doing so that Professor Flitwick would surely award you these points anyway. Oookay then.
 * One could say this of the entirety of The Deathly Hallows Part 1, due to being an Obvious Beta.