The Simpsons features many characters with a Berserk Button.
Though few would argue that golden boy Homer Simpson is the greatest example. In fact, Homer's Berserk Button has arguably been a staple of the character since day one, through all the characters' many changes. Homer's primary Berserk Button is his son Bart Simpson. However, many times Homer's thinly subdued insecurity has led to some of his many explosions of anger. Homer may also fall in line with having a Hair-Trigger Temper. One of the show's most time-honored traditions is Homer strangling his son Bart (never in a lethal fashion, most of the time) due to aforementioned boy doing something to either specifically anger Homer, or more often than not being the cause of a vexing situation for Homer. It's iconically complemented with the catch phrase "WHY YOU LITTLE—!!!" As Homer's explosive temper is almost as iconic a trait as his childish behavior or appetite, there are countless examples of Homer's Berserk Button being pushed throughout the series. Some examples include:
Homer doesn't mind if a food will kill him or have other adverse side effects (he even ate old baking soda in one episode), but HATES if something is "low-fat".
Homer's temper was the subject of a few episodes, particularly the episode "I am Furious Yellow," where Bart makes a successful webcomic called Angry Dad. The comic recreated daily fits of rage Bart observed from his dad. Ironically at the end of the episode however, it's said that it's healthier for Homer to act out on his anger rather than try to subdue it... which when tried had harmful side effects.
Homer was one of the prime suspects in the famous 2-parter "Who Shot Mr. Burns?" episode, where Mr. Burns is... shot at the end of the first part, albeit with very good reason as Burns entered monster territory much further than usual. In Homer's case, the old running gag of Burns never remembering Homer's name comes full circle as Homer tries vigorously to get Burns to remember his name in order to put himself on Burns' good side. It's all in vain however, Burns even going as far as to remember every other member of the Simpson household except for Homer. This finally drives an unappreciated-feeling Homer to the brink of murderous rage, nearly beating Burns before being dragged out by security shouting "Oh you're dead, Burns! You're dead!!" Although Homer wasn't the culprit, and he seemed to have one of the simpler, less urgent reasons to kill Burns compared to the rest of Springfield, suspicion of him came ironically from Burns finally remembering Homer's name (albeit in a comatose state) which nearly sealed Homer's supposed guilt. Later Homer visits him and yells at him to take back his accusation, but it turns out while his name is all Burns can say he still can't put it to his face. Homer strangles him to take back the accusation but then Mr. Burns comes and asks Smithers who the man shaking him is, which in turn pushed his Berserk Button once more. Strangely, Burns continues to forget his name for a few seasons, but Homer doesn't seem to care.
Despite often putting out an attitude of indifference, Homer is actually quite sensitive. He even punched Lenny for no directly personal reason, due to a realization that many of his co-workers laugh at him earlier when at home. This form of mindless anger has often taken Homer into the territory of the Jerkass, most notably in later seasons.
Bart's position as Homer's Berserk Button actually got him institutionalized in an early episode. When taking a Rorschach test, he flew into an angry rage when one of the blots oddly resembled "The Boy".
Marge: I'm sure you'll see my husband is perfectly sane if you just talk to him without mentioning our son Bart. Nurse: There actually is a Bart?! My God!
Principal Skinner usually gets annoyed by Bart Simpson's antics, but the episode "Brother's Little Helper" shows just what happens when Bart presses Skinner's berserk button one time too many when he ended up flooding the entire schoolgrounds with a firehose and a gymnasium during a fire safety skit gone awry: He screamed Bart's name while witnessing Bart laughing during the aftermath, and approached him in a menacing manner. In fact, he ended up having to punch a clown-based punching bean in front of Bart's parents in order to calm himself down before addressing them for the parent teacher conference.
Otto: Your dad was right, I am a bum. Bart: He didnít call you a bum. He called you a sponge. Otto: SPONGE?! (punches wall) Does this look like something a sponge would do?!
And don't ever harrass or harm Bart in any way around Marge. She won't even care if its 99% of Springfield's population, do NOT fuck with Marge.
And if you lose a simple sport like Bart did in "The Boys of Bummer", RUN! RUN FAST.RUN FAR.
And if Maggie is separated from her pacifier, may God have mercy on your soul.
Bart doesn't like it when you make fun of his mother, as seen in "The Great Wife Hope" and "The Devil Wears Nada" (the latter in which her beat up Nelson).
Do not bad-mouth Duff at Moe's. That's just asking for trouble.
When Moe says "Put your beer on a coaster" he means it!