Adaptational Jerkass

While some adaptations make a character nicer, this is the opposite, making a character more of a Jerkass than they were in the original work

While there is some overlap with Adaptational Villainy, the key difference is that a character isn't necessarily villainous. It can be a hero who was made into an Anti Hero, or a villain who was Affably Evil is now Faux Affably Evil.

Compare Took a Level in Jerkass.

Anime and Manga

 * The Pokémon anime's first season wasn't above giving the Gym Leaders a bit of edge to their personalities. They're fairly nice and personable in the games,, but here you get to see Lt. Surge act like a schoolyard bully, calling his opponents babies while his Raichu sadistically beats their Pokémon so badly that they're sent to intensive care. Blaine's also okay with endangering his opponents' Pokémon by making them fight him in an active volcano, Erika will go so far as to ban people from her Gym just because they insulted the perfume she sold at her store, and even Brock and Misty can be real jerks when the situation calls for it. Then there's Sabrina, but she's a straight case of Adaptational Villainy.
 * Sailor Moon has a few examples:
 * Luna in the manga wasn't above scratching Usagi to get her to pay attention, but she always treats Usagi as her student, with firm kindness. Anime Luna has drawn a picture of what happened if Usagi kept gaining weight, berated her on a regular basis for her faults, and would mock some of her, to the point that it's shocking when Luna informs the other girls about Sailor Moon's Heroic BSOD.
 * Mamoru in the manga would tease Usagi, but it was more lighthearted than some of the jabs he would aim at her in the anime. She actually started to fall for him when he started acting more gentlemanly. Anime Mamoru has to take half a season to not see her as a "silly girl" and would deliberately provoke her. Granted, she engineered more of their hostile encounters owing to the number of times her objects -- exam papers, shoes, and so forth-- would land on his head. To his credit, he does mellow in later seasons, and their relationship becomes healthier.

Fan Works

 * Gilbert from Fire Emblem: Three Houses is an emotionally stunted man and a stern absent father who nonetheless loves his daughter dearly. But fics that demonize him such as The Emperor and the Goddess and To Those Who Are Never Coming Home make him an abusive bully who shames Annette no matter what she does, with the latter fic having him slutshame her due to unknowingly dating a married man.

Film

 * Death Note: While Light has always been a murderous Villain Protagonist, the Japanese live-action film series makes him even worse. He becomes more evil more quickly than either the anime or manga, to the extent he's perfectly willing to personally kill his own father to prevent the Death Note from being organized.
 * Harry Potter has a few instances:
 * In the Harry Potter and the Prisoner of Azkaban book, Hermione kept trying to make peace between Crookshanks and Scabbers, but her justifications that Crookshanks is a cat giving into instinct kept falling short as Ron aptly noticed that the cat is gunning for his rat. While she keeps going Never My Fault after it seems that Crookshanks has eaten Scabbers, she eventually apologizes to Ron when he helps her with Hagrid's trial notes. Hermione keeps saying in the film that "Ronald has lost his rat" and doesn't even consider the possibility that Crookshanks has eaten Scabbers. (She's right, but that's not the point.)
 * The oft-mocked scene from Harry Potter and the Goblet of Fire film where Dumbledore, instead of calmly asking Harry if he had placed his name into the Goblet as in the book, immediately starts yelling and interrogating him.
 * The Chocolat novel has Armande Voizon greeting Vianne and Anouk in the streets when seeing them perform a ritual with a black cat. She is a cranky old lady, but she's also nice to those she likes. In the movie, given they come to her while she's napping and ask to rent out her shop, she's a bit crankier and needs time to open up to them.
 * During the In the Heights film, the argument that Benny and Nina had after the blackout is given to Usnavi and Vanessa instead, owing to the fact that Benny doesn't blame her for, telling Nina to stay with the group while he goes help at the dispatch. As a result, however, it makes Usnavi out to be more of a jerk rather than accidentally ghosting Vanessa and worrying her out of nerves.
 * Coraline: in the book, the titular character is very matter-of-fact and polite to her neighbors. Movie!Coraline is a bit more abrasive, making fun of Wyborn after he scares her a few times and mimicking Mr. Bobinsky's way of speaking.
 * This happened by virtue of The Princess Diaries book series eventually surpassing the films.
 * Lana Weinberger is known to be an Alpha Bitch in both versions, but . The first film had none of these moments since Book 9 came out long after production and Lana is nowhere to be seen in the sequel; she remains a vapid cheerleader who mocks Mia for the heck of it, with none of the Hidden Depths she would show later.
 * Principal Gupta in the book is strict, coming down hard on Mia for the times she's come to blows with Lana, which happens quite a bit, but she's pretty fair. In fact, for the ice cream incident, all she asks is that Mia pay for the dry-cleaning on Lana's shirt as well as apologize to Lana, giving her detention when Mia refuses to apologize. She later cancels the detention when Book!Grandmere outs Mia as a princess, half-joking that Mia ought to have told her she was under a lot of stress that week and saying the press drama is punishment enough. Principal Gupta in the films doesn't even know who Mia is until the latter is outed as a princess, referring to her as "Lilly's friend" and clearly buttering up Grandmere for being royalty. While she doesn't punish Mia for the ice cream incident, it's after Lana's friends humiliated her at the beach and besides which the principal didn't see what happened, so Gupta merely advises Lana to send her dry-cleaning bill to the school.

Puppet Shows

 * During Muppet Classic Theater, where the Muppet cast is putting on fairy tale skits, they sometimes do this for the story. For example, Nice Guy Kermit the Frog may play a skeptical mayor who mocks Gonzo for claiming there's a wolf after Gonzo had false alarms the whole day for earthquakes and tidal waves. Gonzo himself, a weirdo but good-natured, plays a "funny little man" that bargains with Miss Piggy about turning straw into gold, and rejects her bracelet as payment because he can see that it's zirconium.

Theatre

 * In Annie, Mr. Warbucks is a little stiffer than his counterpart "Daddy Warbucks" in the original Annie comic. Daddy Warbucks wanted to adopt Annie immediately. In the play, after learning that his secretary Grace chose a girl orphan, Mr. Warbucks asks rather brusquely why she didn't get a boy for the winter holidays. He feels bad, however, when Annie apologizes for not being a boy but hopes that she will be fun anyway, and takes her out to the movies as an apology. After one night, his heart has melted and he asks Annie politely the next day if he could adopt her.
 * Twisted: The Untold Story of a Royal Vizier, the Team Starkid parody, manages to make the Captain of the Guards even a bigger jerk than Razoul is in the Aladdin series, and that's saying something! Razoul hates Aladdin for being a thief and a troublemaker but he has a healthy respect for the Sultan and Jafar, at least until the latter is outed as a traitor. He also eventually warms up to Aladdin when the latter team up in the television spinoff. The Captain of the Guard keeps critiquing Ja'far's way of leadership, saying "This is all Ja'far's fault!" and saying that the vizier's 2Ds department was executed because they weren't producing anything. (Ja'far admits he has a point by nodding his head sadly.) His redeeming moments are his legitimate concern for the men killed at Aladdin's hands directly or indirectly, as well as for the Princess. When finding the Princess at the hideout, the Captain's first concern is ensuring the Princess wasn't hurt or assaulted before arresting Aladdin, and admonishing her for how stupid she was to trust the first stranger that took her home.

Web Original

 * Stupid Mario Brothers has several examples, all Played for Laughs:
 * Far from the happy-go-lucky hero of the games, Mario here is a selfish Lazy Bum who does such things as refuse to cut his vacation short to rescue Peach from Bowser again, on top of.
 * Princess Peach of the game series is a Nice Girl through and through. This Peach is a whiny, nagging Spoiled Brat.

Western Animation

 * Happens in-universe during some film projects for BoJack Horseman
 * Mr. Peanutbutter is definitely not the Nice Guy that he appears as because an overly irrational sense of optimism does not translate into inherent goodness, but one consistent thing is his love for Diane. Thanks to Todd's suggestions, the film Mr. Peanutbutter becomes more complex, but also loses more of his redeeming traits.
 * In the same film, as far as people know, BoJack was not involved with stealing the D from the Hollywood sign. (He was, by the way, thanks to a drug and alcohol trip fueled by jealousy.) The way that Wallace Shawn plays BoJack, he was definitely involved.
 * BoJack himself feels that Diane did this to him with her ghostwriting project of his book becoming a chronicle of their friendship titled One Trick Pony. She lists many embarrassing anecdotes without any of the "and all" that lends to the Warts and All credo that she maintains.
 * Some of the Peanuts characters are a little meaner than they are in the comics, which is saying something.
 * Peppermint Patty can be a little abrasive, but she's generally not that demanding on holidays. "A Charlie Brown Thanksgiving" is about her inviting herself to Charlie Brown's Thanksgiving plans, as well as Franklin and Marcie. When Linus suggests explaining that the Browns are going out of town, Charlie Brown points out that Peppermint Patty doesn't let you get a word in and talks over you. Then she proceeds to complain about the snacks that Charlie Brown, Linus, and Snoopy prepare for the afternoon meal, asking "Chuck" if he knows anything about Thanksgiving dinners. Marcie has to point out that it was rather rude of Peppermint Patty to act this entitled.
 * Snoopy has his moments. In the comics, he and Charlie Brown have an understanding where Charlie Brown tolerates his dog's imaginings, and Snoopy is happy to greet his human. During a brief falling-out where Charlie Brown accidentally cost Snoopy a world record during a baseball game, they agreed to a truce when Charlie Brown offered to make Snoopy the team manager. Some of the cartoons have moments where Snoopy is more disparaging of Charlie Brown and less than emotionally supportive. Charlie Brown also offered Snoopy the manager position when the latter was upset about another baseball game lost, making the grievance pettier.