The cast of ''Manga/FullmetalAlchemist'' have so many recorded Berserk Buttons that it practically requires separate folders for each one.
* '''Edward Elric'''
** Perhaps Ed's most famous Berserk Button is any mention of his [[TheNapoleon vertical deficiencies]]. He usually ends up exaggerating the insult to ridiculous extremes as well as whooping the ass of the offender.
** The only one he won't go nuts on is Al (after all, they're brothers...and someone has to keep him in line), and even ''he'' got away with a knock on the head and a retort of "Don't call me small." Of course, the short rants are constantly a CrowningMomentOfFunny.
** Also, don't suggest that [[SheIsNotMyGirlfriend Winry is his girlfriend.]] At the same time, however, don't even ''think'' about harming a single hair on her head...because Ed will ''kick your '''ass'''''. Like the narrator in ''Brotherhood'' says, [[DeclarationOfProtection he will do anything to protect her]].
** Threaten [[BigBrotherInstinct his little brother Al]] while Ed's around and you'll find yourself very, very, VERY soon regretting it.
** It's also not too much of a good idea to bring up memories of the human transmutation incident for laughs, although this was more of a TranquilFury in the first episode of ''Brotherhood''.
--->'''Ed''': You know...there are some lines you really shouldn't cross.
** The closest Ed ever comes to killing someone is when he has [[spoiler:Shou Tucker]] up against a wall after Ed realizes he [[spoiler:used Alexander ''and'' Nina for his chimera experiment.]] He might have let him go if [[spoiler:Tucker]] hadn't decided to show us all what a bad idea it is to laugh at Ed's worst memory. He was on the road to getting pummeled to death with a steel fist before Al pulled his brother off.
** Also, he really, ''really'' [[DoesNotLikeSpam hates milk]]. [[FridgeLogic Possibly in relation to his... height issues]].
* '''Winry Rockbell''':
** Edward finds himself the victim of Winry's Berserk Button whenever he needs to go back to her for maintenance and (predominantly) repairs. If there's even so much as ''one scratch''...
** Also, never criticize her handiwork. After hearing someone insult her automatic craftsmanship in the first anime, Winry went from telling Ed to calm down to telling Al to let Ed go so he could (more or less) kick the guy's ass.
* '''Roy Mustang''':
** Much like Ed with Winry, it is a very bad idea to even imply that you might harm Riza Hawkeye. Your only chance of surviving such an implication is if he is heavily restrained.
** Don't imply that you're attracted to her, either. In the manga, Barry the Chopper declares that he's in love with Riza (because she shot at him instead of screaming in terror). Then he makes the mistake of putting his hand on her waist, clearly against her wishes, in front of Roy.
--->'''Roy:''' ''[[CrazyJealousGuy *literally growling, eyes on fire*]]'' Stand aside, Lieutenant...there's going to be a ''fire'' tonight.
** Oh, and don't suggest that she really enjoys killing, like Kimbley did when they were all serving in Ishbal. Riza in a CornerOfWoe makes for one really pissed-off Roy.
** Roy is generally a [[TheChessmaster Chessmaster]] who [[JerkAssFacade pretends that he is]] [[ObfuscatingStupidity only concerned with pursuing career advancements and chasing girls shamelessly.]] But if you dare to harm his comrades, he'll give you hell for all he's worth. [[PlayingWithFire Literally.]]
** Chapter 93 of the manga shows that mocking the death of Roy's close friend, [[spoiler:especially when you're the killer,]] is another excellent way to push it.
* '''Izumi Curtis'''
** Izumi seems to have a few of these, and they seem to be set on a hair trigger. Don't call her old.
** Or hit on her when her husband is around. Just because he's a GentleGiant doesn't mean he can't beat you to a pulp when provoked.
** Try to abduct Izumi's apprentices. No, really. Go on. Try. But better have your will signed first.
* '''Other characters''':
** You shouldn't tell Hawkeye that you killed Mustang (even if it's not true). [[NotSoStoic The result is not pretty.]]
** A scene with Greed in the manga shows that calling Envy "ugly" is a great way to tick him off, and get him to turn into his true form to ''kill you''.
** In the first anime, mentioning [[spoiler:Hohenheim]] is a great way to have your face pounded in by Envy.
** Don't threaten or try to kill the first anime version of Sloth. Wrath will go BERSERK on you.
** [[BadassArmy Not that they really need it]], but messing with the Briggs Bears will [[MamaBear earn you the immediate, violent wrath]] of [[FourStarBadass Olivier Milla Armstrong]].
** Gluttony is usually a PsychopathicManchild who just doesn't ''get'' that eating people isn't very nice, but hurt [[LivingEmotionalCrutch his beloved]] Lust and watch him completely flip out.
** Scar does not take well to anyone involved in the Ishvalan genocide. And "does not take well" means "will ''[[YourHeadASplode dissolve your head]]'' via FacePalmOfDoom."
** Ed and Al share a minor (in Al's case, not so minor for quite a while) one that is labeled "Pointing out how GREAT it actually is being a soul trapped in a suit of armor". It led to one pretty not-so-nice brother fight.
** Don't mock Hohenheim's sons in front of him. [[PapaWolf Just...don't.]]
** Any open or implied disrespect of Ling in front of his vassal Lan Fan will result in her giving a DeathGlare to the person responsible, at the very least, or her attacking the offender.
** Ling gets pretty pissed whenever someone, especially those in positions of power such as [[spoiler:Fuhrer Bradley]], try to convince him that leaders should be able to [[YouHaveOutlivedYourUsefulness abandon their followers]].
** Do ''not'' mess with Greed's "[[JerkassFacade possessions]]".