Nicky Santoro in Casino is a subversion; he is less capricious and unruly than Tommy DeVito, being unlikely to kill on a whim, but is shown using extreme violence in a much more calculated fashion. Also, Nicky shows a bit more respect for his friends than Tommy does. He even gets a Pet the Dog moment with his son and another where he gives money to one of his mooks to help support his kids after the mook gambled all his money away. While Tommy has a raging Inferiority Superiority Complex driving his violence, Nicky has no such problem with his self-esteem and uses violence exclusively to gain money and maintain power. Of course, as an already "made man" in the Chicago outfit, Nicky has less to prove.
Pesci's earliest example is Joey LaMotta in Raging Bull. LaMotta spends most of the movie getting bullied by his big brother Jake, who has a much worse temper, but takes the time to have at least one Pesci freak-out.
In JFK, Pesci plays an ex-CIA agent named David Ferrie who is so paranoid about the government agents who are going to kill him if anyone starts poking around JFK's assassination, that Garrison's mere hint that he wants to talk to Ferrie about something private throws Ferrie into a psychotically paranoid panic that renders him incapable of doing anything but drop the F-Bomb.
Pesci's character from 8 Heads in a Duffel Bag is basically a more subdued version Tommy from Goodfellas - who has all the hair trigger of the other character but is smart enough to know that shooting everything in sight just because it's annoying him is a bad idea - he makes do by making very sincere promises to kill everyone later instead. In the end, however, he decides against it.
Pesci's character Harry in the first two Home Alone movies probably also counts, though his outbursts consist of mutterings of "ratcha fratcha" instead of intelligible profanities. Allegedly, Pesci managed to fill the on-set Swear Jar in roughly a day.
Ultron in Avengers: Age of Ultron, since he's a ten-foot tall heavily-armed robot with the emotional intelligence of a two-year old. Prime example: after Ulysses Klaue makes a deal with him and furthers Ultron's Evil Plan, Klaue suggests Ultron is a creation of Tony Stark's (which he is). Ultron promptly rips Klaue's arm off. He then apologises profusely for his outburst, saying he didn't understand why he did that...before remembering Klaue compared him to Tony Stark, and kicking the man down the stairs.
Walter Sobchak (John Goodman) in The Big Lebowski is an unbalanced ex-Vietnam soldier with serious rage issues who will pull a gun on someone over a bowling league dispute.
Interestingly, among the cut scenes was a discussion revealing that Walter was never actually in 'Nam; his habit of bringing it up is just a shallow attempt to excuse his own issues since the number of people likely to actually contest that point in the face of Walter losing his shit is almost nil (basically just Jeff Lebowski).
In Black Zoo, Michael Conrad has a hair-trigger temper and the least little thing will set him off. Any outsider who earns his wrath is likely to become the target of his big cats.
Frank Booth from Blue Velvet takes this trope to truly disturbing levels. He'll get extremely angry and start yelling and cussing (although he does that pretty much all of the time away), if not get outright violent over even the slightest thing he deems out-of-tune, such as looking at him or not, or not bringing him his beer right away. This alone makes him an extremely unsettling and terrifying individual to deal with.
Tugger from Brick is high-class muscle and the second in command of "The Pin". His tendency to fly into a blind rage at the slightest provocation makes him more trouble than he's worth, however, and causes numerous serious problems throughout the movie.
Albert Spica from The Cook, the Thief, His Wife and Her Lover. He holds court at his swanky restaurant every night, pretending to be sophisticated while he threatens and assaults anyone who even slightly annoys him. This is made more gruesome by the fact that he tends to force-feed his victims inedible objects.
Robert Downey Jr. in Due Date, whose character's outburst gets him kicked off the plane and placed on the "no-fly" list, kicking off the movie plot. His wife even mentions his temper.
The Exception, former Kaiser Wilhelm II has a short temper, understandable after more than twenty years of being blamed for Germany's previous misfortunes that weren't entirely his fault and having a crippled left arm his whole life. His adjutant Sigfurd and his wife are worried that Wilhelm's temper exploding at Heinrich Himmler, head of the SS, will get him killed. They know this because Hitler had the former German chancellor Kurt von Schleicher and his wife killed in the Night of the Long Knives in 1934.
This is Grindelwald’s (the Big Bad of Fantastic Beasts) Fatal Flaw. In his backstory, he would have been able to keep Dumbledore on his side if he hadn’t flown off the handle and tortured his siblings. In the second film, if he hadn’t slaughtered a bunch of people in Paris in a bout of rage, Newt’s niffler wouldn’t have been able to get the MacGuffin that was stopping Dumbledore from personally fighting him.
Girlfight: In the beginning of the film, Diana has so much difficulty controlling her anger that she starts fights at school.
Sonny Corleone is the most emotional and violent brother of the Corleone family in The Godfather. Try to touch his sister Connie or someone from the family and you'll trigger out his Berserk Button, though this was his weak point and he got gunned down to death.
The titular character in Happy Gilmore has serious anger management issues, he says in the opening narration that it happened after his father’s death, he will fly into a rage and attack the person who annoys him at the slightest provocation, he does gradually get better as the film progresses as Virginia Venit coaches him to get his anger issues under control.
How to Rob a Bank: Simon, the head bank robber, has some severe anger management issues and keeps popping anti-psychotics. His reaction the battery in his phone going dead is to hurl the phone at the head of te police negotiator.
In Jurassic World, any animal listed as having a high Aggression Index on the website. I. rex, however, has a "Very High" Aggression Index, as do the Velociraptors. In the latter's case, no one besides Parental Substitute Owen Grady is safe from their claws and teeth — and even that relationship is very tenuous, as Owen himself knows.
In The Loft, Philip is a cocaine addict who is prone to sudden and unpredictable fits of explosive rage; evn at his own wedding.
Kevin "O-Dog" from Menace II Society. Imagine a black, slightly more trigger-happy version of Tommy DeVito from Goodfellas and you have O-Dog. In the opening scene, O-Dog and the main character are in a liquor store and suspiciously watched by the proprietors. After they pay for their drinks, which they have already started drinking, the cashier tells O-Dog that he pities his mother. O-Dog responds by killing him and his wife and stealing the surveillance tape, which he proudly plays for his friends.
Mr. Furious in Mystery Menclaims to have this trope, but it's pretty clear that it's all an act. This is important, as he also claims he has Unstoppable Rage... which, it turns out, he has. He's just so mellow by nature that he has to be seriously provoked to actually enter it.
In Pain & Gain both Daniel and Paul snap at things that seem very insignificant in hindsight. Paul regrets this, while Daniel seems to embrace it. It seems a lot like typical steroid aggression.
In Please Murder Me!, Craig paints Joe Leeds as having one, as a justification for Myra shooting him in self-defense.
In the film Primal Fear, a plot point is that Aaron Stampler, a stuttering boy accused of brutally murdering an abusive archbishop, when under enough stress, switches into another sociopathic persona named Roy, a textbook example of this trope. At the very end of the movie, it's revealed that Aaron not only murdered the archbishop and another girl, but he had made up the Aaron personality to win the case, establishing himself as a Manipulative Bastard.
The Professional: Norman Stansfield. Not only does he lose his control in nearly every scene he is in but he swears and screams at the top of his lungs even to his henchmen and bosses.
RoboCop: Emil Antonowsky is infuriated when Murphy accidentally shoots the gang's stolen TV, telling him "Your ass is mine".
Scarface (1983): The protagonist, Tony Montana, is practically the epitome of this trope. Almost everything sets him off, from betrayal to guys getting to his sister. It's made even worse when he's high off his own cocaine and really flips his lid in this case. Of course, he pays the price and as a result, his violent rage costs him his life when he is finally gunned down in the end.
Don Logan from Sexy Beast is described by actor Ben Kingsley as the unhappiest man in the world, Logan is clearly hated even by his friends and colleagues. Upon arriving in Spain, he is given a cold and awkward reception by his old friends, who are clearly terrified of him. Once they go against his wishes, however, he launches into a nearly unending tirade of abuse and self-pity, painting their every action is a personal affront to him. After he is ultimately killed, his boss doesn't even bother taking revenge for the murder, since he didn't like him.
Captain Byron Hadley from The Shawshank Redemption is an angry, amoral man who constantly swears and attacks people in almost every scene that he is in. At the beginning of the film, he brutally beats a prisoner to death simply for crying because it was his first night in prison. He ultimately reveals himself as a coward by "sobbing like a little girl" when he's finally brought to justice and sent to Shawshank as an inmate; it's not at all hard to understand why.
Doyle Hargrave in Sling Blade. Luckily, he gets his comeuppance at the end of the film.
Eddie Miller, the antagonist in The Sniper, is a tightly compressed ball of rage waiting the smallest trigger—usually provided by a woman—to set him off. The best illustration probably occurs at the amusement park, where he goes from pitching baseballs with pinpoint accuracy at the trigger plate for the dunk tank to hurling them directly at the woman in the tank.
In Starkweather, Charlie can go from seemingly calm and polite to a raging fury in the blink of an eye.
A New Hope has Cornelius Evazan, who decides he and his companion Ponda Baba don't like Luke Skywalker for no particular reason and then gets violently aggressive when Obi Wan tries to defuse things.
Evazan: (pointing at Ponda Baba) He doesn't like you. Luke: I'm sorry. Evazan: (yanks Luke back by the shoulder to face him) I don't like you either. You just watch yourself. We're wanted men. I have the death sentence on twelve systems. Luke: I'll be careful. (turns away) Evazan: (yanks Luke back again) You'll be dead! Obi Wan: This one is not worth the effort. Come, let me get you something. Evazan angrily shoves Luke out of his seat.
Anakin Skywalker in the prequels is a rare heroic example of this trope. Whenever something bad happens or especially if someone he loves in danger, he will be very impulsive, hot tempered, and violent. Then again, Anakin doesn't stay a hero for long — it's this very temper, combined with the fear of losing those he loves, that ends up driving him to The Dark Side and leading to his transformation into Darth Vader.
Like his grandfather before him, Kylo Ren in The Force Awakens. Unlike his grandfather, He seems to prefer to take it out on inanimate objects, but if the nopetroopers' reactions are anything to go by, they don't trust him not to do the same to them. And that's before things really start to go off the rails.
Francis Begbie from Trainspotting. He picks fights for disturbingly minor provocations, including one incident where he blamed a man eating chips of spoiling his pool shot. However, Begbie also intentionally provokes fights for no other reason than that he's addicted to violence and mayhem. In the book, Begbie is described as a large and imposing man, but director Danny Boyle decided to imply a Napoleon Complex by casting the fairly short Robert Carlyle.
Conspiracy Brother in Undercover Brother flies off on overly-paranoid, outraged (and often absurdly ill-informed) The Man-is-keeping-me-down rants on the flimsiest of provocations. Even someone cheerfully saying "Hi, Conspiracy Brother!" in greeting is guaranteed to send him spiraling off into a rant about how everyone assumes that black people spend all their time getting high.
"Brother, when you get a minute, could I get a list of the words that trigger these fits?"
Conspiracy Brother doth protest too much. He actually does spend a lot of his time smoking pot. His paranoia is in no small amount due to this.
Al Capone from The Untouchables (portrayed by Pesci's friend, Robert De Niro) whenever he is not a Hypocrite gangster in public, is easy to piss off with a single failure or even in an attempt to cross him. In the court, he had to be held by several men when his lawyer turned against him or else he could have made another baseball bat scene 2.0.
Cody Jarett from White Heat is another iconic example of a Hair-Trigger Temper.
White Wolves II: Legend of the Wild: Beri is prone to yelling at people when she's frustrated, and not in a nice way.
Fisher in Wild Tales has many angry outbursts through his misadventures at the towed-car lot, the city council desks (where he completely loses it and starts battering at the clerk's booth with a fire extinguisher), the arbitration audience for his divorce and the mining company he attempts to apply to. When his car gets towed away from the second time however, he slips into a state of Tranquil Fury to properly set up his revenge.
In Back to School, Professor Terguson is played by Sam Kinison, so of course he snaps pretty readily, but even for Kinison, he sounds like a lunatic.
(After a student gives an account of why the Vietnam war was a disaster for America that isn't very flattering of American policy, Terguson gives a strained smile) Terguson: Is she right? Cause I know that's the popular version of what went on there, and a lot of people like to believe that. I wish I could, but I was there. I wasn't in a classroom, hoping I was right, thinking about it, (starts to get angrier) I was up to my knees in rice paddies, with guns that didn't work, (starts getting louder) going up against Charlie, slugging it out with him, while pussies like you, were back here partying, putting headbands on, doing drugs, listening to the Goddamn Beatles albums! (begins doing Kinison's trademark scream)