The cast of ''Manga/FullmetalAlchemist'' have so many recorded Berserk Buttons that it practically requires separate folders for each one.
[[folder: 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.
** Take note, at one point, he thought to himself that he was lucky being so small made it easy for him to crawl through air ducts. ''He had to fight the urge to punch himself in the face.''
* 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]].
* Don't touch his little brother Alphonse either.
* Also, he really, ''really'' [[DoesNotLikeSpam hates milk]]. [[FridgeLogic Possibly in relation to his... height issues]].
[[folder: 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 goes from telling Ed to calm down to telling Al to let Ed go so he could (more or less) kick the guy's ass.
[[folder: Roy Mustang ]]
* He doesn't take kindly to being reminded that he's useless when wet.
* Don't imply that you're attracted to Riza Hawkeye, or mess with her in any way, shape or form. 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.
* Don't hurt his subordinates. He hand-picked those five soldiers for a reason and they are his ''family''. He has no problem with tearing across town and jeopardizing a secret mission if any of them are in danger.
* And don't let him find out that you're the one who [[spoiler:murdered his best friend]]. ''Nothing'' will save you.
[[folder: 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.
[[folder: Other characters ]]
* What it says up there for Roy Mustang regarding Riza Hawkeye? It goes the other way too. She's not BodyguardingABadass for nothing.
* 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.
* 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.
** The human transmutation incident is also not a good thing to bring up with either of the Elric brothers. When Shou Tucker, who had already [[spoiler:fused Nina with her dog Alexander in a horrible crossing of the MoralEventHorizon]] brought it up in an attempt to imply that he and Ed were NotSoDifferent, it led to a vicious NoHoldsBarredBeatdown by Ed, who came very close to ''killing him'', followed by a soft-spoken warning from Alphonse that Tucker needed to stop talking.
* 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 "[[IJustWantToHaveFriends possessions]]".
* Don't ''ever'' insult Hohenheim's sons.