History BewareTheNiceOnes / FanWorks

* "[[https://archiveofourown.org/series/2166906 Wild Child AU]]" depicts a world where Godzilla essentially adopts Madison Russell after his battle with the [=MUTOs=] as he assumed her family had died in the battle, resulting in Godzilla and Mothra coming to see Maddie as their child. When Madison returns to civilisation during [[Film/GodzillaKingOfTheMonsters2019 the confrontation with Ghidorah]], she is briefly abducted by a group of soldiers with the idea of selling her to Titan enthusiasts. Although Maddie manages to escape, when Mothra learns what had happened she causes the kidnappers' helicopter to crash, the usually benevolent Titan outraged that those humans dared to harm Maddie.

** [[BadFuture Dark World!]]Derpy is another example. She's still a kindhearted {{Ditz}} and probably one of the nicest mares you could meet, but she's the new Element of Loyalty and has spent the last thousand years walking nonstop around Discord's castle, making her ''very'' strong ''without'' using her new SuperMode. She proceeds to help the rest of the Mane Cast defeat the blackbirds that have spent the last thousand years trying to eat her daughter (who was [[ForcedTransformation turned into a muffin]]) and send them to Ponythulu's realm to be eaten. Later on, the Valeyard makes the mistake of spending the entire fight with him tap dancing on her {{Berserk Button}}s. The result? [[spoiler:She crosses the RageBreakingPoint and ''[[NoHoldsBarredBeatdown beats him to death]]'' after his [[SoulJar Regeneration Template]] has been destroyed, ignoring his [[VillainsWantMercy pleads for mercy]].]]

* ''Fanfic/FashionUpgrade'': Damocles realizes this is true of [[PapaWolf Tom]]. The principal believes the man is like a Great Dane, large and fearsome looking but ultimately harmless. He nervously realizes that the man is actually more like a Pitbull, gentle and loyal to those he loves but very vicious towards anyone that threatens them.
* ''[[https://archiveofourown.org/works/7088386 Red For Fortune]]'': The normally sweet Marinette gets especially scary when she confronts Adrien about a Mᴏᴅᴇ issue with a fashion spread supposedly inspired by the Lunar New Year, comprised of stereotypical outfits designed by his father, modeled entirely by white people in {{Yellowface}}, ''including Adrien himself''. The fact that [[DiggingYourselfDeeper Adrien resorts to trite defenses of everyone involved rather than even try to comprehend why she's so upset]] ends up [[BrokenPedestal destroying the pedestal]] she put him on by the end of the chapter, and then gets her akumatised.

-->[[https://www.fanfiction.net/s/5398503/30/Embers Katara]] is [[FanFic/EmbersVathara not honest]]. [[WesternAnimation/AvatarTheLastAirbender Katara]] is sweetness and confidence and "we're going to help Aang save the world!" Until she runs into [[BerserkButton something she doesn't like]], at which point the Sugar Queen cracks, and a lot of nastiness oozes out. ...Yeah. That relationship is going to end ''[[SarcasmMode so well]]''. I think I'll take my chances with [[LawfulEvil Azula]]...

* ''[[https://m.fanfiction.net/s/10264509/228/Tales-of-Fairies The Gender Bend Cliche]]'': Luca Heartfilia, [[GenderFlip the male version of Lucy]], is a proper gentleman that is always kind and understanding to many of his guildmates. That said, like his canon and other Fairy Tail mages, he's more than willing to fight to protect his love ones, such as delivering a GroinAttack to Jose [[CaughtMonologuing when he was bragging about using the job to take Luca back to his father as an excuse for Phantom Lord to crush Fairy Tail]] or deliver a CurbStompBattle [[WouldHitAGirl to Evergreen]] when she petrified their guildmates during the Battle of Fairy Tail arc.

* When Isabela, Luisa, and Mirabel overhear a random villager that they are better off without Bruno in ''Fanfic/HisDaughtersTheMiraclesOfTheFamily'', Isabel has the man strung up with vines and forces him to apologize.

* [[Fanfic/ANewLifeEra]] has ''two'' characters who have demonstrated this trope: The Hacker, and his son, Moe, both beating up a bully more massive than they were at the age of 10.

* In ''[[https://archiveofourown.org/works/52815058 Coffeenette]]'', Marinette is widely regarded as a NiceGirl... that is, as long as she's well rested. If she isn't, [[MustHaveCaffein a good cup of coffee]] will help restore her. But when she doesn't have coffee... well, her classmates do their best to either stay out of her way or just write their last wills for a reason.

* Makoto is a very kind-hearted and loving person in ''Fanfic/TheNaekawaProject'', but his anger is something that terrifies Toko. When Shizuku, one of her mothers, attempts to slap her after she spells out how abusive she was, he grabs her hand in a vice-like grip, simply telling her too shut up, replacing his anger with fear.

* In ''Fanfic/SomeSemblanceOfMeaning'', heroine [[ShrinkingViolet Vale Whitaker]] is probably one of the most sweet-natured, timid tributes in the Games. She hates the idea of harming another human being. This same girl [[spoiler: lividly stabs another girl in the chest after the latter attacks Vale's district partner Kit]], and after [[spoiler: one of the Gamemakers' mutts kills Kit, Vale goes into what could be described as a berserker rage the next time she sees the mutt, jumping on it and hacking at it until it's dead and she passes out]]. To say nothing of the distrustful snark she unleashes on [[JerkWithAHeartOfGold Obsidian Citrine]], even if he's being perfectly friendly to her.