As each member of the Straw Hat Pirates has a lifelong ambition, disrespecting these dreams are the easiest way to piss them off.
* The whole Straw Hat Crew:
** Don't treat people like garbage or that they are somehow beneath you. A good chunk of the crew have suffered this at one time or another and won tolerate people that act this way. Just ask the World Noble that Luffy sent flying with a punch.
** Don't treat your fellow crew members badly as the Straw Hat crew is as close as family and see anyone seriously mistreating their crew mates as scum.
* Monkey D. Luffy:
** Don't touch his NiceHat (a memento from his idol).
** Don't disrespect the title of Pirate King (it's okay if you lay honest claim to it; he'll see you as a WorthyOpponent instead).
** Don't disrespect the Jolly Roger by stealing or defacing it.
** Don't steal his food, especially when it's meat, his TrademarkFavoriteFood (he's a justifiable BigEater).
* Roronoa Zoro:
** Do not disrespect his dream or the idea of fulfilling a promise (his ambition to be the best swordsman in the world is a promise he made in memory of Kuina).
** Do not make light of Luffy's ambitions in his presence. He made a pledge to serve him and he intends to keep that pledge.
** Do not hurt any of his crewmates. Chopper and Robin getting badly injured by Ohm and Eneru respectively caused him to vocally wish revenge on them.
* Nami:
** Do not spend money without consulting Nami first. Do not steal anything from her, especially if she stole it first.
** Crewmates acting stupid in front of her tend to make her pull out the [[ArmorPiercingSlap Armor Piercing Punch]].
* Usopp:
** The LovableCoward who would rather run away than fight, even post-TimeSkip. But if you insult Luffy in front of him, you're doomed; he may be the weakest of the Straw Hats, but he's still a OneManArmy when he needs to be, and like Zoro, he won't put up with insults to his captain. Mr. 4 and Miss Merry Christmas found this out the hard way, ''after'' hitting him with enough force to kill a normal human a thousand times over.
** Mocking his father Yassop is a quick way to piss him off.
* Sanji:
** Sanji's biggest berserk button is when anyone wastes food, [[ChefOfIron including 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.
** He won't stand for it if somebody insults his cooking.
** His original wanted poster had an ugly composite sketch. Bringing it up was bound to draw {{Death Glare}}s from him.
** Do not bring up [[IncompatibleOrientation Kamabakka]]. Remembering his two years in "hell" are enough to ignite in rage and/or open up a king-sized can of kick-ass.
** Don't say that Sanji is incapable of protecting anyone. Doing so is a one-way ticket to finding his boot planted in your face.
* Tony Tony Chopper:
** Do not make light of medicine, and ''don't'' be a doctor who's ''OnlyInItForTheMoney''. Learning this from Dr. Hogback really pissed him off.
* Nico Robin:
** Do not disrespect history, and especially do not ''destroy'' it, [[http://www.youtube.com/watch?v=PQc16Ri1cHQ as she demonstrates]] on Yama in the Skypiea arc. Her goal is to seek out the truth about the Lost Century which has been lost in time, so she honestly thinks there is much at stake.
** She also gets angry when people talk about her past and why she got her bounty (either because it touches on the first reason, destroying history, or because of the BlatantLies told about her to keep the world turned against her)
** [[{{ArsonMurderAndJaywalking}} She's not fond of docking (a goofy combination attack that Franky and the others came up with), either.]]
* Franky:
** Do not take his speedo or do anything to dent his macho image.
* Brook:
** 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... NobodyTouchesTheHair!
** Do not make light of life, as Brook's is intimately aware of the fact he's living a second life.
** Another one that's PlayedForLaughs: in ''Anime/OnePieceFilmStrongWorld'' 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. This BerserkButton is pushed again in Chapter 682, when the little dragon from Punk Hazard looked disappointed that Brook didn't have any meat on his bones. This actually serves as a minor plot point, as it reveals that Kinemon also hates dragons, but for a much darker reason. Unsurprisingly, however, when he comes across animals who have a taste for bones, he's not any happier.
As for everybody else...
* Averted by Hatchan when Zoro cuts his hair. [[AvertedTrope He... decides to forgive Zoro because it's only hair and it'll grow back.]]
* Gekko Moria has two notable ones. First is his old crew of TrueCompanions, who were massacred by Kaido; just thinking about it is enough to provoke a VillainousBreakdown. Almost as big of one is stating, or even just implying, that he's weak.
* If anybody mocked Eustass "Captain" Kid's dreams about becoming the pirate king, he wouldn't hesitate to straight out kill them for that.
* Bartolomeo, a character who first appeared in the Dressrosa arc, was introduced as a rude, AxCrazy {{Jerkass}}. It's bad enough if you provoke him at all, but he absolutely ''worships'' Luffy; say one bad word against him in this fanboy's hearing, and it will be the last thing you ever say.
* Kelly Funk from the Dressrosa arc, a boxer short in stature and temper with [[{{Glass Cannon}} prodigious strength]] [[{{Fragile Speedster}} but no endurance at all]]. Call him shrimp or anything of the sort, and he'll pummel you within an inch of your life. As for the "no endurance" part that makes him less than a threat to those who are at least as strong as he, his Devil Fruit powers let him merge with his brother, a GentleGiant with a [[{{Mighty Glacier}} ridiculously strong]] [[{{Stone Wall}} and sturdy body]]. When that happens, the threat level [[{{Lightning Bruiser}} skyrockets]].
* Donquixote Doflamingo has a notable one: People who bear the name of D.