Love Makes You Crazy

"Trinity: You wanna make a deal? How about this? You give me Neo or we all die, right here, right now.

Persephone: She'll do it. If she has to, she'll kill everyone here. She's in love.

The Merovingian: It is remarkable how similar the pattern of love is to the pattern of insanity."

- The Matrix Revolutions

Being in love can cause a person to behave strangely or irrationally, a tendency which is often exaggerated in television and film. Usually played for laughs in SitComs and anime, it can be used as a motivation for villainous (or at least uncharacteristic) behavior in more serious stories. However, it can also result in behaviors that are presented as being noble, though unusual.

A special case of this is the Stalker with a Crush, who often shows other irrational behavior as well. Psycho Lesbian is another special case, meeting obvious conditions.

If the writers have a deeper understanding of relationships, they may have "true" love not cause this effect, contrasting it with the crushes we've seen elsewhere in the series. This is relatively rare, though.

If two characters are the romantic rivals in a Love Triangle, one may become a Rival Turned Evil. This is especially common in daytime soaps.

The Chick Magnet and Hello, Nurse! make everyone they meet crazy.

For people who hold this as their viewpoint about love, see Silly Rabbit, Romance Is for Kids. Of course, things could be worse...or better. Compare Yandere. For the Romantic False Lead going crazy to make the relationship easier for the official couple, see Derailing Love Interests.

Anime & Manga
{{quote|"Love makes people act weeiirrdd!"}}
 * School Days... for the love of GOD, do these two girls go axe-crazy over this guy-to the point that they'd happily murder each other in broad daylight, with witnesses, just to be rid of the competition.
 * Dr. Tōfū in Ranma One Half would begin acting bizarrely whenever Kasumi Tendō is around, or even simply mentioned. This makes him very dangerous as he'll often be in the middle of treating a patient, and once bent Ranma's neck at a ninety degree angle.
 * This also covers Ranma's fiancées (Akane, Shampoo, and Ukyō) fairly well. When first introduced to the series, they conduct their courtships in a relatively calm, normal fashion. As Ranma continues to ignore them, they slowly grow more desperate -- and more extreme. Magic, deception, violence, all of these become legitimate avenues of pursuit towards romantic happiness. Ranma's rivals, meanwhile, enter the series in this state.
 * Kodachi Kunō, on the other hand, was already crazy before love even entered the picture.
 * Mazinger Z: Dr. Hell can be a subversion because he was already quite unstable and troubled before... but when he was in college and fell in love with a cute Japanese exchange student he started behaving obsessively (getting angry if someone dared to spend time with her) and erratically (his grades started slipping because he was too obsessed to study). And when he found out she was in love with another person, he flipped out completely and tried to Murder the Hypotenuse (and even stormed into the campus with a shotgun!).
 * Boss also tended to act in a very dumb, irrational and even obsessive way when he was in presence of Sayaka or Jun Hono. Sayaka tended to ignore it, but Jun did not appreciated it or found amusing.
 * Brock in Pokémon, who is usually the rational Big Brother Mentor to Ash and Misty (or May, Max and Dawn), tended to lose his cool around beautiful women; especially Nurse Joy or Officer Jenny (and since both are everywhere, this quickly became a running joke with him proclaiming the latest one was the fairest of them all).
 * Strawberry Panic: Shizuma (aka Etoile-sama) can make Nagisa freeze or even faint just by looking at her a certain way. Typically the character who has this effect on a person is unaware, but Shizuma knows and seems to like doing this.
 * Yu-Gi-Oh! GX: Manjyome is a loner who seems to want to be the Badass Longcoat Rival, but he loses all control of himself and turns completely insane around Asuka.
 * And then there's Yubel.
 * Gendo in Neon Genesis Evangelion is a Magnificent Bastard who wants to become a god. It all boils down to his entire life being miserable until he met his wife Yui. Then she died, and Gendo snapped.
 * Three years of False Start after False Start when she tries to approach Sakaki have left poor Kaorin of Azumanga Daioh with more neuroses than a Woody Allen film festival. She's fine when she's thinking about something else, but once she sees Sakaki... or thinks about Sakaki... or has a dream about Sakaki... et cetera... she becomes an odd combination of Clingy Jealous Girl and Cannot Spit It Out.
 * Higurashi no Naku Koro ni has . This does not end well . A more fitting trope for her than Yandere due the cause of her craziness.
 * One Piece: Boa Hancock badly misinterprets innocuous actions as signs that Luffy reciprocates her love for him. This would seem cute and innocent and so not creepy if she didn't happen to be pushing thirty. Her behavior has a uncomfortable resemblance to a certain Real Life psychological disorder. (Then again, given all the crap she had been through early in life, her screws may not have been put in quite tight enough before she met him anyway...)
 * Fridge Logic makes this truly scary when you realize she's the last person in the world you want to turn into an all-out Yandere.
 * It may also be Fridge Brilliance, if you see Boa Hancock/Luffy Ship Tease as a parallel to Hippolyta's attraction to Heracles, which ended rather badly, or Circe's unrequited love for Odysseus, despite him being the only one to resist her charms.
 * One of the creepiest examples comes from Minoru Murao's Knights manga. Of all people,  goes nuts when she assumes that the object of her affection Mist is physically involved with his Ms. Fanservice companion Euphemia. Her response is to  . Keep in mind that this guy saved her life in the first few chapters, which is why she's so hung up on him in the first place. This is borderline Love Makes You Evil. To her credit, she does eventually realize just how utterly screwed up she was, and works to undo her actions.
 * Fruits Basket: Kagura Sohma is the sweetest little thing... until something gets between her and Kyo....
 * In Basilisk, Action Girl Hotarubi is... well, not exactly "there" when something bad happens to her husband, Yashamaru.
 * Not to overlook Kagerou, who gets insanely jealous of Oboro . Oboro's choices may also be love-crazy, depending on your perspective.
 * Mirai Nikki: Yuno is singlemindedly devoted to Yukiteru.
 * Although it's hinted that she was already insane long before she fell in love with him.
 * Lucy's love for  in Elfen Lied drives her to go insane and  . She was partially insane before that anyway though.
 * Possible example in Bleach:
 * Well he was there to save her and not anyone else, so when he transformed...
 * from Loveless is known to have  Have we mentioned that Ritsuka is only twelve years old? And that he's his brother?
 * Zetsuai 1989 is all about this trope. Let's see: when Izumi was five, his mother discovered his father was cheating on her, and murdered him in front of Izumi so that she could "possess him completely". Then there's the Yandere fan Eri, who . And that's without even mentioning the multiple examples of Kouji being driven to despair, self-mutilation, or generally self-destructive behaviour because of his love for Izumi -- who is understandably a bit freaked out by all this. At first. After a while, he starts to join in...
 * Gunter from Kyo Kara Maoh. At first, Gunter seems a little like an idiot, or perhaps more like a teenage girl in love. He tends to be rather overprotective of Yuuri, fussing over every little thing and freaking out whenever he goes missing. Supposedly (at least in the manga), Gunter was actually quite the organized, professional man before he met Yuuri.
 * And in Wolfram's case, at least where Yuuri is involved, love makes you very very very protective and clingy.
 * Damn near everyone in Durarara. It's essentially "Love Makes You Crazy - The Series".
 * Saika actually has this as a power: she takes control of her main host by slowly wearing them down with incessant whispers and promises that she can give them any friend, companion or lover they want if they just sit back and let her handle it ("handle it," of course, being defined as "stab the target and infect them with The Virus so that they become an unquestioning slave to the Hive Mind"). It's only by virtue of being a Broken Bird that doesn't really get what love actually is that her current host,, has been able to resist it for five years and counting.
 * In .hack series, Harald's obsession toward Emma Wielant (even after his death) was what caused him to create the beta version of The World, Fragment, both of which are actually . And guess the source of the network crisis that happen throughout the series...
 * Mayo -- 3rd Fushigi Yuugi OVA. She's so infatuated with Tamahome that she's willing to destroy his world (both literally and figuratively) just to be with him.
 * Poor Nina Einstein. She started as an inoffensive Shrinking Violet, only to develop a crush on Princess Euphemia after she saved Nina (and others) from terrorists, and went kinda loopy, earning her the label of The Scrappy among the fandom. Then It Got Worse:
 * The ultimate cause of Tsubasa Reservoir Chronicle, as both motivation of the villain Fei Wong (who wants to resurrect the technically-not-dead  and also at one point the motivation of the hero (it's crazy due to what they are both willing to do- it's evil, yes, but also completely fucking bonkers). At a specific point in the backstory the hero, in the madness of love, chose to turn back time so he could save the girl he was in love with. This act borked the entire time-space continuum.
 * Since the two series are connected, this means that love driving people nutso is also the source of xxxHolic. It is, in fact, the source of the main character, since.
 * Some fans theorize that even Cardcaptor Sakura was caused by this love driving people nuts, as it is suspected that it was all part of the plan Clow Reed set up to overcome Fei Wong's Evil Plan to resurrect the aforementioned not dead person. Needless to say, a plot driven by so many {{The Plan plan-happy]] nutjobs is not the easiest thing to follow.
 * Inverted in the Wild Series. When they have a master, manbeasts will not lose their minds and attack humans, and that bond is based around love (whether they want it or not). So basically, love makes you sane in this case.
 * In Virgin Love, Kaoru believes this based on his mother's behaviour and shuns all emotional relationships for that reason. When it finally happens to him too, his lover is willing to accept the Crazy Jealous Guy side of him and persuades him to stay together.
 * Oz in Pandora Hearts for Alice. He'll do anything for Alice. {{spoiler|Will go temporarily insane after witnessing human!Alice's death. Will tear apart the Abyss and almost Alice herself to get rid of anything that hurts her.}}
 * Gil for Oz and Vincent for his older brother Gil.
 * Puella Magi Madoka Magica has Sayaka Miki, whose love for a childhood friend is unfulfilled, driving her berserk, {{spoiler|and eventually turning her into a huge mermaid monster.}}
 * Belarus from Axis Powers Hetalia is described as being relatively cool-headed. That, is, before she fell in love. She cornered Russia in a closet, made him cry, and carries knives in her dress to threaten people who get too close to him. Not to mention, he's her brother.
 * Shion in No. 6 for Nezumi. When Nezumi is threatened, Shion switches from either all-out rage or coldly, completely rational and murderous. In the novels, {{spoiler|he comes close to strangling a man when he tries to kill Nezumi and declares it to be "punishment."}} In episode 10 he  {{spoiler|murders a guy in cold blood who tried to kill Nezumi}}.
 * The Zako Soldiers spell this trope out at the end of one of their ZakoZako Hours.
 * The Zako Soldiers spell this trope out at the end of one of their ZakoZako Hours.
 * Rune in Karakuridouji Ultimo towards Yamato.
 * Kisshu from Tokyo Mew Mew towards Ichigo. He tries to Murder the Hypotenuse in order to have Ichigo for himself and even resorts to trying to kill Ichigo herself if she refuses his advances.
 * Ciel is implied to be this way for his fiance Elizabeth in Black Butler. Under any other circumstances, Ciel would not go anywhere near the big, creepy castle without Sebastian. Unless, of course, Elizabeth has gone missing and he has every belief that she is in there and in trouble. Then he'll do anything. Including giving Grell pretty much permission to rape Sebastian in exchange for backup. Not crazy enough for you? How about after he realizes all the girls in the castle are living dolls, he ditches Grell in order to run deeper? And still keeps looking for Elizabeth after being told he was next to be turned into a doll?
 * Still not enough proof? What about in the game, Black Butler: Phantomhive and Ghost Ciel nearly had a panic attack when Elizabeth fainted. He was so concerned about her that he fell asleep while looking after her unconscious form; a situation most likely not happen if it were another person.
 * In the manga, Ciel throws himself in front of a bear without a second thought to protect Elizabeth. This act also shows Elizabeth's mother, Frances Middleford, that Ciel is more worthy of being her daughter's future husband than she had originally given him credit for. Still, that could be considered more heroic than crazy, since Ciel knows that if he is in danger of getting hurt, Sebastian can easily save him.
 * Grell is like this for Madame Red and later Sebastian.
 * Louise in Zero no Tsukaima whenever Saito's involved.
 * Koharu no Hibi: Koharu in regards to Akira. She stalks him, obsesses over him, and devotes her whole life to him. In chapter 21 she even told him she would die if he asked her to.
 * Ai no Kusabi has Guy, who is so in love with Riki, not only does he {{spoiler|give Riki a penectomy to remove the pet ring that was on his penis upon being told that as long as Riki wears Iason's pet ring he'll never be free of him, but he also blows up an entire fortress in an attempt to kill Iason}}. Second example is Iason, who, like Guy, becomes extremely obsessed with Riki. It's not touched upon in the old OVA, but the novel and audio drama have scenes where Riki slept with a female pet, and he was subsequently brutally tortured by Iason. Not to mention the number of times Iason forces Riki into having sex with him.

Comics

 * From DC comics, we have the Star Sapphire Corps, whose power is fueled by love. Originally the power was consolidated into a single person, and as a result this trope was mainly the sort of love that fit into this category.
 * This trope is taken quite literally with Harley Quinn.
 * In an issue of Swamp Thing, "My Blue Heaven" (written by Alan Moore) has Alec trapped on an alien world all alone. He uses his plant-controlling powers to create clones of himself... and then, in a moment of temptation, creates his love Abby. After spending another day creating an entire populated world, he accidentally creates a John Constantine who warns him how crazy he's become. It doesn't help that Alec can't ignore the fact he can't get Abby's smile just right, and he goes mad when his Abby-self responds "All love... is madness."

Film -- Animation
"Megara: People always do crazy things when they're in love."
 * Hercules:

Film -- Live Action

 * In the classic play and film The Dybbuk, Khonnen, a poor student, and Leye, a rich merchant's daughter, fall in love. But her father makes her marry a rich man's son. So Khonnen studies the Kabbala, and -- using what is effectively black magic -- dies and becomes a spirit who takes over Leye. (At the wedding, he makes her shout to the groom, "You are not my bridegroom!")
 * Evelyn Draper in Play Misty for Me.
 * Alexandra "Alex" Forrest in Fatal Attraction.
 * Lisa Sheridan in Obsessed.
 * Martin Burney in Sleeping with the Enemy.
 * The central theme of the film Wicker Park.
 * The English Patient. The title character, his lover, and her husband were already all a little crazy, but love seems to really bring it out.
 * Singin in The Rain. "I'm singing in the rain..."
 * Gene Kelly does a similar routine in It's Always Fair Weather, but on roller skates.
 * Bitter Moon. What starts out as a beautiful love story between a man and a woman ends up as two people who have destroyed each other and themselves.
 * Raging Bull. Jake over Vicky. Admittedly he was already pretty crazy but meeting her made him worse
 * Dance with a Stranger. Based on a true story
 * My Summer of Love has aspects of this
 * Zorg in Betty Blue. Betty was already crazy
 * Harvey Keitel over Kate Winslet in Holy Smoke
 * Jeremy Irons in Damage if you consider travelling from London to Paris just to spy on someone crazy (which most people presumably would)
 * Mulholland Drive
 * Basic Instinct though you can argue its more 'Lust Makes You Stupid''
 * In Throw Momma from the Train, this line is used, word for word, as the last line of Billy Crystal's book. "Hate makes you impotent, Love Makes You Crazy, somewhere in the middle you can survive."
 * Crazy Stupid Love
 * Esther in Orphan.

Literature

 * The subtitle of Wuthering Heights could be "Love Makes You Crazy"... "and Evil."
 * Edmund Bertram, previously the Only Sane Man at Mansfield Park save for the heroine, falls blindly in love with Mary Crawford at the expense of all higher reasoning and discernment.
 * The Warlock from The Tales of Beedle the Bard tries not to love by removing his own heart. When he tries to love again....
 * In Only the Ring Finger Knows, Yuichi Kazuki is known at Wataru Fujii's school for being kind and polite to everyone he meets, despite possessing ridiculous amounts of beauty, wealth, and talent. Yet whenever Wataru crosses paths with him, Yuichi never fails to be snarky and insulting towards him. Karin, Wataru's sister, comments that this must mean that Yuichi either really hates him... or really likes him. Guess which one it turns out to be.
 * Bellatrix Lestrange from Harry Potter could qualify for this, seeing as she's utterly obsessed with her master in an... "unhealthy way". Although she already had a husband, Word of God stated that Voldemort was her true love.
 * Richard and Jessamyn in Swordspoint, as well as Richard and Alec and basically everyone else in the book and its sequels to a lesser extent.
 * In A Song of Ice and Fire, crazy Lysa Arryn is largely motivated by her love for Littlefinger, who uses this to his advantage. And as implied by his actions, ie:  Littlefinger himself has been left mentally unhinged by his unrequited love for Lysa's sister, Catelyn Stark.
 * In Robert E. Howard's "Shadows in Zamboula," after the woman tells him her love went mad and attacked her, Conan the Barbarian tells her her beauty could do that; she denies it; he was drugged.
 * In Warrior Cats, there is Ashfur. After being dumped by Squirrelflight, he, to make her feel the same pain he did.
 * Lydia in Caught In The Act by Peter Moore in regards to Ethan.
 * Vlad Tepes in Count and Countess. To get to Elizabeth Bathory's time period, he has to somehow outlive his natural lifespan. The measures he takes become increasingly more frantic and sadistic.
 * In the Dresden Files several characters suspect love was the underlying reason behind The Summer Lady's Aurora actions. Also the Winter Lady Maeve and the new Summer Lady Lily suspect that The Queen of Winter's Mab actions are motivated by love. And they are visibly disturbed by the notion. Maeve in particular implies that it is very dangerous for powerful magical beings of the Never Never to be in love. It twists their worldview and throws them completely out of their comfort zone.

Live Action TV

 * A main theme of Battlestar Galactica Reimagined seems to be "love makes you batshit".
 * In Farscape John tells Aeryn she's the reason he's crazy. Of course, all that Mind Rape by evil guys might have something to do with it.
 * It doesn't just turn you crazy in Supernatural, it makes you a suicidal martyr willing to sacrifice yourself for the one you love.
 * Nearly everyone in Pushing Daisies is a victim of this, and it's not always even romantic love.
 * In Jekyll,
 * iCarly: Ms. Ackerman wants to know where Spencer is for every minute of every day, and actually keeps logs on when he doesn't answer his phone.
 * In a platonic!love (or not?) kind-of way, Sam got really, really mad when Carly was harassed by a bully in "iMake Sam Girlier"
 * Buffy the Vampire Slayer: Don't ever hurt or kill one of Willow Rosenberg's girlfriends, lest you want to end up flayed alive.
 * "Love makes you do the wacky." -- said twice in the episode Some Assembly Required. First time by Willow, in reference to Angel jealous behaviour toward Xander, and then by Buffy, about why a classmate revived his brother as a sort of Frankenstein's monster.
 * In Skins, Effy's love for Freddie literally makes her crazy: she's eventually sectioned for either schizophrenia, depression, or both.
 * Noah's Arc:.
 * Often a case with patients in ER. After the death of his granddaughter caused by a crazy bomber who happened to be taken into the same hospital, the man who was previously shown to be friendly and calm went and strangled the guy to death. When Gates's best friend's wife finds out he was dating Neela, she got drunk, went to the ER and flew into a rage at both Gates and Neela. In another instance, when a man found out his girlfriend was dying, he brought in a gun and threatened the doctors working on her to continue working on her and bring her back, even though her heart had stopped.
 * Characters of As the World Turns often go to pretty extreme extents for their family and love interests.
 * This is actually a standard trope of many Soap Operas, usually combined with Derailing Love Interests as heretofore normal, decent people, usually women, go completely off the deep end in an effort to hang onto or seek revenge on former love interests.
 * Bus Driver Stuart Benedict, of The Adventures of Pete and Pete. Almost every time we see him, he's just been dumped by his on-and-off girlfriend Bus Driver Sally Knorp, and he reacts increasingly poorly. On various occasions, the break-up has caused him to spend the bus ride home giving a six-hour tour of important locations in his and Sally's life; go insane upon hearing "If Your Happy and You Know It"; and drive to the Arctic, tattoo her name to his chest, strap himself to an iceberg and drift out to sea (though we don't know if he went through with that last one. He shows up again afterwards, so he probably didn't.)
 * On Doctor Who, Rory loves Amy. A lot. Enough that he
 * Although that was arguably more like love keeping him sane.
 * River loves the Doctor. A lot. Enough that she
 * Cole in Charmed. It may have also made him evil, again, but then again it could have been all the demonic powers he absorbed.
 * Then again again, he absorbed all those powers in order to be able to return to the mortal plane to be with her again.
 * In Desperate Housewives, Edie, who up until that point was a casually promiscuous woman who was more bitchy and snarky than actually crazy. Once she starts having a liking for Carlos, suddenly she starts going completely insane and even attempts suicide just to get his attention.
 * Chris Keller in Oz for Beecher. And Ryan for Dr. Nathan. Also overlaps with Love Makes You Evil.
 * Shane Walsh in The Walking Dead.

Theater
"And as he errs, doting on Hermia's eyes, So I, admiring of his qualities: Things base and vile, folding no quantity, Love can transpose to form and dignity: Love looks not with the eyes, but with the mind; And therefore is wing'd Cupid painted blind: Nor hath Love's mind of any judgement taste; Wings and no eyes figure unheedy haste: And therefore is Love said to be a child, Because in choice he is so oft beguiled."
 * Polonius is initially convinced that Hamlet's recent wacky behavior is caused by his love for Ophelia. His attempt to set up a sting operation to prove his theory ends with an apparently-deranged Hamlet ranting that he'd never loved Ophelia, and that she'd best go be a nun (or a whore, depending on your interpretation). So much for that idea.
 * In A Midsummer Night's Dream, Helena is aware that her passion for Demetrius is wacked out even before she betrays Hermia and Lysander to him.


 * Othello insists that his flaw is that he "loved not wisely, but too well." Of course, being a Horrible Judge of Character doesn't help either.

Music
"So why am I here at your door, at your door. If I was sane, I'd take my crazy behind, And get back in my BMW"
 * Steven Curtis Chapman explains in "Something Crazy" that you don't know what love is until it makes you do something crazy. He mentions a street corner preacher, a humanitarian in Uganda, and the biggest one of all, Jesus Christ.
 * Bruno Mars seems to be fond of this trope.
 * The song Grenade may sound upbeat. But when you listen to the lyrics, it's kinda disturbing. Voluntarily giving your life for someone that no longer loves you? That's not sweet. That's sick.
 * In the music video, he drags a piano around with him to her house. While it seems strange at first, observe how the piano could stand for the suffering for not being loved by her anymore. He reaches her house, to see her kissing another man. Depressed, he leaves, standing in front of a railroad crossing, playing the piano.
 * A more literal example of this trope, the song Talkin' To the Moon takes a similar approach to Grenade, but instead, it depicts a man who has been driven stark raving mad instead of being Driven to Suicide over a relationship. Here, the person is revealed to be talking to the moon...pretending the moon is his once significant other.
 * While the tone of this song is Lighter and Softer when compared to Grenade (though the music sounds sadder), imagine if you broke up with your significant other. You no longer have any interest in him/her. You've completely moved on and wish to find someone else. Meanwhile, that person you dumped is left emotionally compromised by your relationship with him/her, that he/she is driven mentally insane...to the point where he/she ends up talking to a figment of his/her imagination: You. He slowly deteriorates under his own delusions of being in love with you while you don't even know about it.
 * "Voices in My Head" is the most literal example of this.
 * Taylor Swift's song The Way I Loved You is all about this trope. "I'm so in love that I acted insane; that's the way I loved you."
 * Jojo says herself when singing about her "Boy Without A Heart"


 * In Pink's "Please Don't Leave Me" she slowly goes insane when her boyfriend attempts to leave her.
 * The Police's "Next to You". Love makes you sell your possessions and contemplate theft, apparently.

Pro Wrestling

 * Many of Randy Savage's angles that involve Miss Elizabeth invoke this trope.

Video Games

 * Salome, the former disciple of Makai Kingdom's Overlord Zetta, whose crush on said Overlord goes into this trope on the deep end. Upon learning that Zetta has been cursed by The One and has only two days to live, Salome, who is dying herself, then tries to make Zetta marry her so they can die together...by crashing her own netherworld into Zetta's and eventually provoking him into killing her.
 * Persona 3's nearly dooms the world in an attempt to see the person she loved again.
 * In the new Prince of Persia.
 * That's more a case of Love Makes You Dumb.
 * Or it might be a case of Love Makes You Genre Savvy, as the epilogue
 * Craft of Mega Man Zero 4 is either this or Love Makes You Evil. He joined Dr. Weil's army only so that he can protect Neige, the girl he loves. When the latter fled from Neo Arcadia because of the iron-fisted rule of the Big Bad, he makes it his mission to bring her back (thinking that she will be safer in Neo Arcadia), all while spearheading Operation Ragnarok, which would obliterate any inhabitable area outside of Neo Arcadia. Neige did eventually talk Craft out of working under the Big Bad, only for him to.
 * This is how the original Blood Omen: Legacy of Kain begins: When Nupraptor the Mentalist, guardian of the Pillar of the Mind, discovers that his lover Ariel, guardian of the Pillar of Balance, has been murdered in cold blood, he goes completely insane and secludes himself in his mountain retreat. Which wouldn't be so bad by itself, except he has a mental link with all the other Pillar guardians, who all become corrupted by his madness in turn.
 * In Half Minute Hero, the so-called "Beautiful Evil Lord" went completely insane after learning that his beloved Millennia was kidnapped by an Evil Sorcerer named Noire, and vowed to cast the spell of destruction because he felt that a world without Millennia wasn't worth living in. You, the Hero, come along and try to calm him down by beating up Noire and returning the Evil Lord's girlfriend to him. You can also attempt to try and tackle him head-on first to snap him out of it by force (and you get a Cosmetic Award title for doing so), but because the Evil Lord is hopped up on equal parts adrenaline and angst, you'll get beaten repeatedly unless you take enough time to Level Grind to the point where you can face him on equal footing.
 * And he goes insane again later when Millennia's transformation into a bat suddenly worsens.
 * In City of Heroes, the Clockwork King is hopelessly in love with Penelope Yin, a young psychic. His love for her manifests in the Clockwork Army which he uses to keep her safe from heroes and other boys.
 * His Praetorian counterpart Metronome has the same feelings for his world's Penelope.
 * This is Played for Laughs in George's Image Song, "Ai no Sengen". Yeah, that's right. Played. For. Laughs. If you want the more tragic versions, you can certainly find that in many other parts of the series.
 * In Lux-Pain,
 * Rule of Rose:
 * In Arc Rise Fantasia,  takes a dive off the slippery slope to evil and onto the crazy train when she finds out that she's an Unlucky Childhood Friend. Nice Girl to Yandere Vamp in about five minutes or less!
 * Happens to Kirby in the Kirby 64 good ending, where Ribbon kisses Kirby. Cue the hearts that float into the sky.
 * Isn't that more Post-Kiss Catatonia?

Visual Novels

 * Denny, Professor Capek and in Shikkoku no Sharnoth.
 * Tsukihime has Roa. Arcueid is so beautiful! How can I make her like me? Oh I know, I'll make her turn me into a Dead Apostle so I gain immortality, steal some of her power, turn her against every other being like her and then turn up in random towns for the next eight hundred years so she has to come find me and kill me! Man I'm smart, this is sure to work.
 * To be fair, at least in Ciel's route the implication is that he doesn't KNOW it is love.
 * Arcueid actually has the same trouble telling how she feels towards Shiki. She doesn't know why she gets all emotional around him, upset if he breaks a promise and spends so much time thinking about him. The idea is raised that maybe Arcueid hates him or something but that's obviously not the case.
 * in Fate/stay night, who at one of her more sympathetic moments in UBW is extremely stressed over the actions she's been taking. They're horrible things she never would have done in life on top of her not believing her plan will actually work, but she's desperately struggling nonetheless. It would help if it was easier to read what was really thinking. It's not even entirely clear to the reader whether her affections are reciprocated.

Web Animation

 * In Draw With Me, the boy

Web Comics
"Violetta: And here I kept expecting you to attack him. Vole: Dun be schtupid. She vould rip my fangs out."
 * Oasis from Sluggy Freelance cranks this trope up to 11 until she finally winds up in a mental institution.
 * In The Dreamer, Alan infiltrates Gen. Howe's ship just to rescue Beatrice.
 * There's a mild version in Penny and Aggie, where Duane reflects on how his crush on Penny affected him.
 * Girl Genius, which is not that surprising.
 * Gil intentionally gives Wooster a free excursion to The Madness Place: "...and there is nothing I couldn't do, had I cause! And now... Now I have one!"
 * When the castle "really flips out" and thus "her beaux" are in danger, Agatha "really flips out" too. Later she spouted a fairly crazy (though it works) How Dare You Die on Me! speech.
 * Vole may be big and mad, but he wasn't born yesterday, so during the Big Damn Kiss he didn't even try to intervene with his Ax Crazy act:


 * El Goonish Shive got Melissa, Unlucky Childhood Friend of Justin. Who told her he isn't attracted to her because he's gay. So she shared this grief with her rumour-mongering sister and everything quickly rolled downhill from there. She had fits of delusion that she could seduce Justin and revert the break if she tried harder -- until he couldn't stand hearing her name. Sometimes managed to Dope Slap herself out of this, got another boyfriend, but... still continued to slip into this.
 * In No Rest for The Wicked, the Beast proposed two hundred and forty-three times, but wonders whether giving her a magical ring was too forward.

Web Original
"I've had my car stereo rigged to play "Making Love" out of nothing at all. I've received more drunk dialing more than anyone who ever dated Charlie Sheen. And I've had live bunnies airdropped into my house."
 * New Vindicators features quite a few characters who go through this. Ryan Mueller develops a loving obsession with Katie Merrick, things don't go so well for her when she doesn't reciprocate his feelings. Also Rift develops into an Ax Crazy Yandere after her feelings for Michuru Bradshaw reach critical mass.
 * Todd in the Shadows' love for Obscurus Lupa reaches this.


 * In return, The Nostalgia Chick keeps going further into insanity (and she wasn't exactly all there anyway) for Todd. On facebook, she's even willing to have sex with his corpse.
 * For a less violent and more sad example, at one point in the My Little Pony Friendship Is Magic fanfic "Dawn of a New Day", Twilight Sparkle becomes so pent up over her inability to confess her feelings to Rainbow Dash that she enters a delusional state and spends several hours believing that she has and they are dating. She snaps out of it later, though.

Western Animation
"Arnold: Hi Ruth... Hi Ruth... Hi Ruth... Hi Ruth... Hi Ruth...
 * Kim Possible's interactions with recurrer Josh Mankey (and a few other select young men) cause her to do some irrational things when she really ought to know better. Josh isn't actually a bad guy, but fans tend to vilify him for the influence he holds over Kim. Trouble with romantic relationships remains her major Achilles Heel for the entire series, to the point that Dr. Drakken's ultimate plan to stop her from interfering during The Movie involves a new boyfriend. Sidekick Ron is not much better, doing crazy stuff for almost any reason all the time, but on Kim it's far more noticeable given her usual hyper-competence and level-headed nature. By contrast, her Relationship Upgrade with Ron in Season 4 has so far had no negative effects on her behavior.
 * The Maximal Silverbolt in Transformers: Beast Wars, despite being as heroic and noble as they come, did some highly illogical things for the love of the Predacon Blackarachnia, mainly because of the aforementioned heroism and nobility. Of course, in the end he was right about her, but it was foolish at the time, and he was punished for it. In this case, the other Maximals thought love had made him crazy, when in fact he just had some insight.
 * All over the place in Hey Arnold!! Besides Helga's complete obsession with Arnold, whenever Arnold is around Ruth (and later, Lila), he ends up acting very nuts indeed.

Gerald: There goes one sick kid."

"Patsy: Because love makes us do crazy things! Lazlo: What?"
 * Camp Lazlo: Patsy lies to Lazlo that she is a professional snake hunter who knows Kung Fu. Lazlo believes her, until they end up running from a (tiny, cute) snake and are cornered. Patsy confesses to having lied, and Lazlo asks why.


 * Trixie from The Fairly Odd Parents, in the episode where Timmy wishes the two of them were the last people on Earth. This is weird, since she was sane relative to everyone else on the show before.
 * The reason she's crazy is because she's used to many people being interested in her instead of you know... being one of the two last people on Earth.
 * In the third episode of the second season of Winx Club, after Brandon falls off a cliff, Stella (who was unable to transform at the time) actually jumps after him.
 * Foster's Home for Imaginary Friends: One episode featured a newcomer called Berry. Berry is initially sweet and polite, but once she develops a crush on Bloo she turns into psychotic Green-Eyed Monster who continually tries to get rid of Bloo's best friend Mac so that she can have Bloo to herself.
 * Galaxy Rangers: Zach Foxx is normally The Stoic, a by-the-book contrast to the more "colorful" crew he's commanding. That is, until the Queen put his comatose wife near death with her "dream machine" stunt. Queue The Captain breaking into a high-security facility, holding a technician at gunpoint, and impulsively resigning his commission to embark on a suicide run. Of course, the Mind Rape aspect of that machine didn't help matters...
 * Code Lyoko: Where to begin?
 * Jérémie Belpois. To put it bluntly, he willingly puts his entire world on the brink of malevolent A.I. apocalypse just about every day for the sake of maintaining a relationship with Aelita.
 * In "The Chips Are Down", when Ulrich finds out that Yumi may have to move to Japan due to financial issues, he memorizes the day's winning lottery numbers, reverses time, fills out a lottery ticket, and hands it to her family.
 * Despite what one might think, it's more of an Informed Attribute with William Dunbar. Around Yumi he's more of a Stalker with a Crush -- about the worst he's done (in regards to their relationship) is follow her home to try and kiss her. He does, however, love to brag about how love makes him crazy -- "totally insane", in fact -- and he was expelled from his previous school for putting up poster-sized copies of love letters everywhere (including on his principal's car).
 * Batman: The Animated Series. Hoo, boy, Harley Quinn. She falls in love with The Joker of all people, and is as crazy as he is -- perhaps worse, since she's treated as callously as anyone. Her story of meeting The Joker is the Trope Namer for Mad Love.
 * The Penguins of Madagascar's Rico is already Crazy Awesome, but when love comes into the equation...
 * "Kaboom and Kabust" includes an explosive "Falling in Love" Montage between Rico and his newly-discovered enabler King Julien. His permissiveness whips Rico into an increasingly wild frenzy, until it's all the other penguins can do to contain his destructive rampage to part of the zoo.
 * In "Hello, Dollface", his beloved Ms. Perky doll gets a voice chip, and he does everything she says... to the point of, much to Skipper's horror.
 * Kick Buttowski gives us Jackie... aptly nicknamed "Wacky Jackie" by many of the characters on the show.

Real Life

 * STFU Marrieds is a treasure chest of many real-life examples.
 * Romantic love is in fact linked to high levels of dopamine. Dopamine is linked to schizophrenia. Love actually makes you crazy.
 * A study noted that the behaviour associated with the initial stages of romantic love is functionally indistinguishable with the behaviour associated with obsessive-compulsive disorder.
 * As one could imagine, being Genre Savvy enough to observe What an Idiot! you're being about the whole thing only makes it more frustrating.
 * Made even worse when the person is indifferent to friendly towards you, but is clearly not focused on you as a romantic option. Now you have to fight the urge to gamble away hours of your time for a low return on their attention, compounded with your initial attraction. You just cannot win.
 * Eminem and Kim Mathers
 * David Blakely and Ruth Ellis
 * Tracie Andrews and Lee Harvey
 * The Lighter Side of relationships that end up needing Restraining Orders fits under this. There's only so much bad poetry, unsolicited messages and overtures one can take before annoyance builds to level usually reserved for telemarketers and things that get stuck in your teeth without any floss handy.