Berserk Button/One Piece

• Monkey D. Luffy of One Piece. He has two; run far, far away if you damage his hat, or hurt one of his best friends -- or for that matter, one of your own. Very nicely seen here.
  • The entire plot of One Piece seems to be based around this. If you fight Luffy without having hurt one of his friends, you at least have the possibility of victory. If you hurt one of his group... not so much.
  • Massively subverted in one fight with Kuma. The man made the Straw Hat pirates vanish one by one, and Luffy couldn't do anything about it.
    • But Kuma didn't actually hurt any of them.
  • And if you hurt one of YOUR group members, you are so screwed. Boa Hancock & sisters, we're looking at you.
    • Also, let's not forget Captain Kuro, whom Luffy defeated in righteous anger for turning on his own crew.
  • Also, Buggy the Clown. If you insult his clown nose, he will freak out, and given the chance, he will shoot you with a cannonball capable of destroying several city blocks. When you account for the fact that he tends to mishear things and assume they were insults to his nose...
  • Robin is also quite angered by those who destroy ruins, as she demonstrates on a Mook and Yama in the Skypiea arc. She also gets angry when people talk about her past and why she got her bounty often because what they're saying is not true.
  • Don't call Chopper a tanuki; he'll go Muscle Point on your ass.
    • Yeah, not really; insulting Hiruluk or Kureha would provoke him, but he never really does anything worse than yell and glare if he's called a tanuki, a gorilla, or - most recently - a stag beetle.
  • Sanji will beat anyone who mistreats the ladies to a bloody pulp, especially if the lady in question is his dear Miss Nami. Also, he often goes batshit when called weak or something like that. And if you don't like his cooking or his table service and vocalize it? You're so dead.
  • He also goes psycho if someone so much as shows him his badly-drawn Wanted Poster; clearly whoever made it didn't have a good photograph, and it looks pretty... unflattering.
    • And don't let him catch you wasting food either; that's a big one. That includes using food to fight with. He and Old Man Zeff almost died of starvation when Sanji was a child, so this one's very understandable.
  • Zoro is normally the type of guy who doesn't take revenge on things. But once, Ohm's traps brutally cut and mangled Chopper...
    • From that same arc (Skypiea), he also got really pissed off at Enel when he electrocuted Robin for trying to convince him that the Golden Bell was somewhere on Upper Yard in an attempt to prevent him from destroying the island until he finds it. Doesn't stop Enel from kicking his butt, though.
    • He destroyed Kaku after being at best evenly matched throughout their fight after Kaku started insulting Robin. "You ran your stupid mouth too much."
  • Recently, we get one for Boa Hancock: You so much as lay a hand on Luffy, and not even a Logia Devil Fruit Power will save you from the Snake Princess tearing your ass to shreds. Yeah, when Sengoku mentioned that Hancock is strong? That is NO Informed Ability, she's the strongest Action Girl in the whole world.
  • If you so much as injure any Shanks' friends (such as Luffy), expect Shanks to show no mercy.
  • Go ahead, do anything to seriously harm any of Whitebeard's "Sons." Go on, do it. Then pray to whatever deity you worship that he doesn't find you.
  • Portgas D. Ace can be seen as a deconstruction of this trope because in the Marineford arc, when he was rescued from execution, he let his emotions get the better of him. When Akainu starts to insult Whitebeard, Ace is drawn into a hopeless battle that ultimately kills him. This happened despite everyone, including Whitebeard, warning him to run away.
  • Hurting Franky's Family is ill-advised. And when you talk bad about Franky's adoptive father Tom or taking his speedo, prepare for the worst.
  • Brook's afro is precious to him as it is the last defining feature he has that his old friend Laboon can recognize him by. So ... Do. Not. TOUCH. THE. AFRO.
    • As of chapter 645, Brook hates people who wastes lives. And considering his past, this is understandable.
    • In One Piece Film Strong World when man-eating ants ignore Brook because he was considered "leftovers", he angrily states it was "a bit inconsiderate" and proceeds to cut all the ants down.
    • Brook also doesn't take the idea of his True Companions being attacked, or potentially killed, very well (again, understandable, due to his past).
  • Hilariously averted by Hachi when Zoro cuts his hair. He ... decides to forgive Zoro because it's only hair.