David Banner: "Don't make me angry. You wouldn't like me when I'm angry."
Step by Step: Frank, when he got angry — particularly protecting stepdaughter Dana or biological daughter, Al. Frank (along with Cody) once beat up a dozen ruffians in a bar on the bad side of town by themselves. Later, when he confronted a corrupt TV advertiser about using Al in a 1-900 sex hotline (when the commercial was supposed to be for suntan lotion), he tore apart the office and nearly threw the young man to his death from a high-story window unless he confessed and turned over the master tape to him.
In Heroes, Niki Sanders's alter ego "Jessica", who has super-strength, mostly appears whenever somebody else threatens her son or otherwise angers her.
In The A-Team episode "Without Reservations", Face is shot during a hostage situation in a restaurant. Murdock spends most of the episode in a state of Tranquil Fury, until right near the end, when he finally gets his hands on the guy who shot Face, starts pounding him relentlessly, and actually has to be restrained before he finally stops. It's really not a good idea to hurt someone Murdock cares about.
In the Doctor Who episode "The Runaway Bride", after seeing the Doctor bring down the wrath of a Time Lord on his enemies, Donna points out just how creepy Unstoppable Rage is, especially coming from the hero, and questions whether we should be rooting for it.
Donna: That place was flooding and burning and they were dying and you stood there like...I don't know, a stranger.
As seen in "Turn Left," he would've died there had Donna not been there to stop him from going too far.
Do NOT threaten his companions. Seriously.
Case in point: After a companion is kidnapped in series 6, the 11th Doctor blows up an entire legion of Cyberships just for some information (and to prove a point) and forms an army to storm the guilty party's base. This quickly backfires in a spectacular fashion, but still.
The Daleks seem to induce this in the Doctor quite a lot. When the Ninth Doctor runs across a stray Dalek captured in a museum, he has a meltdown in which he rants and raves at it about the Time War and sadistically gloats about massacring its species before torturing it with electricity until he's physically dragged away kicking and screaming. When the Eleventh Doctor again encounters Daleks masquerading as Allied weapons during WWII (dashing his belief that he had once again slaughtered them all in the previous season finale), he works himself into such a fury while trying to get the Daleks to reveal their identity he winds up uncontrollably whaling on them with a metal pipe while hysterically screaming semi-coherent threats and insults at them. Both times, he really freaks out his companions and various bystanders by suddenly plunging into a seemingly uncharacteristic near-psychotic rage at the sight of these squat, hammy, plunger-armed pepper-pots, despite displaying reason and pacifism with his enemies on other occasions.
Jack Harkness of Torchwood, while a generally calm man, does go into a rage whenever his team is threatened and, due to his immortality, he's hard to stop.
Although he's usually the epitome of The Stoic, really piss Teal'c off, like with what happened in the episode "Talion," and he will stop at nothing until you are dead. It's a Jaffa revenge thing, y'see.
This almost happens in an earlier episode when he finds out that his wife remarried.
Data gets a brief one of these in the first part of the Star Trek: The Next Generation episode "Descent", resulting in him killing a couple of Borg with his bare hands. This was also, technically, his first ever experience of emotional rage.
When Glory drives Willow's girlfriend insane, Willow attacks her with black magic, actually managing to hurt her despite Glory being a hellgod. This foreshadows her Dark Willow phase - when Warren shoots Buffy and kills Tara, Willow flays him alive, goes after his partners, fights her own friends when they try to stop her, and nearly destroys the world.
Giles goes after Angelus after the latter murdered Jenny Calendar. With a flaming baseball bat.
Seen several times with Buffy herself; during her first fight with Angelus, he initially has the upper hand before he goes overboard with his taunts, after which she beats him up and backs him into a corner, but stops just short of killing him, instead settling for kicking him in the groin and walking away.
On the Angel end, we have Angel's near-killing of Wesley after the kidnapping of Connor. Gunn, Fred, and several orderlies could barely haul him off of Wes.
Angel: YOU THINK I'D FORGIVE YOU? NEVER! YOU TOOK MY SON! I'LL KILL YOU! YOU'RE A DEAD MAN, PRYCE! YOU'RE DEAD! YOU HEAR ME?! DEAD!! DEAD!!
Never ever make Admiral William Adama angry, because not only will you get the most terrifying Death Glares on TV but he'll make sure you are dead within three episodes. For instance, when he suffers a mutiny, he flies into a Foe-Tossing Charge to the CIC, and the mutiny leader surrenders before he gets there. He has on two occasions bludgeoned a Cylon to death—a humanoid and a centurion.
Beware the Nice Ones: In the finale, in order to resolve the conflict between humanity and the Cylons, the Final Five have to share memories to give the Cylons what they want. Problem is, one of them killed another's wife. Tory tries to emphasize that they need to just live and let live before they start the process, but when Tyrol learns that she killed Callie, he pulls out and strangles her to death then and there, a look of pure anger, rage, and hate on his face.
In season one The Mole Nina Myers tells Jack Bauer that the Drazens have murdered his daughter Kim. This proves to be the single biggest mistake that the bad guys ever made that season, as Jack then proceeds to storm their compound in a truck and go to town on everyone with both guns blazing.
In any given Garo Episode, the basic rule is that if you mess with Kaoru, call her a bitch, threaten her, or take one of her paintings and scratch a coin against it, KougaSaejima will hunt you like an animal, and he will go on a Roaring Rampage of Revenge until what was wronged is made right. He's done it in the finales of both the original series and Makai Senki, brutally killing both Big Bads, one of whom was a friend of his from his training days as a child. The other was the former student/killer of his father
In the iCarly episode "iMake Sam Girlier", Sam snaps out of her attempts to become more feminine and launches right into a bout of screaming rage after the new bully in town pushes her best friend Carly to the floor.
Also when Freddie handcuffed Gibby to her.
"OPEN THE DOOR, BENSON!!!!!"
Crops up in Professional Wrestling at times; it's typically called 'Hulking Up'. The bigger you are, the more you can get away with here.
Hulk Hogan built a whole career on this trope, getting beaten badly in the early minutes of his fights only to become unstoppable and nearly invulnerable to his opponent's attacks once he hulked out.
This was also a key part of Tazz's gimmick in ECW, to the point where Joey Styles would often ask, "Who can stop the path of rage?"
Parodied in The Avengers. Normally unflappable spy Steed gets thrown around by a bigger, better fighter. His eventual victory takes place off screen, with Steed's boss Mother narrating the villain's fatal error: He made Steed angry.
Mork and Mindy: Mork from Ork, at least twice. Once when Klansmen deface Mindy's home when they find out she's Polish (he returns the favor to their lodge), and again when a robber hits and bullies Mearth in a bar. Also counts as Crouching Moron, Hidden Badass.
Similar to the example in Sword of Truth, Legend of the Seeker takes it one step further by having Kahlan's eyes go blood-red, scream loudly, and gain the ability to confess multiple people remotely (which, apparently, also allows her to confess a Mord'Sith without killing her). The first time it happens when Darken Rahl taunts her by saying that he will use her powers to confess Richard. She actually expels the needles stuck in her with such force that they stick into Rahl's wizard's neck, leaving Zedd the last wizard of the First Order. The second time happens when she finds out that Cara killed her sister, forcing Richard to hold her down, as Cara escapes. The last time (due to cancellation) happens in the finale, when a Sister of the Dark manages to confess Kahlan. When the heroes, with assistance from Mord'Sith, try to kill the Sister, Kahlan again flies into the Con'Dar state, confesses the Mord'Sith and has them kill each other. She then tries to confess Richard but fails, so she stabs him instead.
The title character from Kamen Rider Kuuga is normally a pretty nice guy that wants nothing more than to protect people's smiles. That said, do not piss him off. When a sadistic Gurongi Tribesman by the name of Go-Jaraji-Da (also known more simply as the Porcupine Gurongi) pushed him too far in episode 35, the result was a brutalNo-Holds-Barred Beatdown that ended with Godai finishing him off with a rage-fueled Rising Calamity Titan attack.
This is at the core of Kamen Rider Agito's Burning Form. The angrier Agito gets, the more powerful it becomes. However, somewhat subverted as it's not as strong as its evolution, Shineing Form, which doesn't require rage.
In the Criminal Minds episode "100", Aaron Hotchner gets into a fight with George Foyet, a spree killer who is obsessed with him after he has kidnapped and murdered his wife. Foyet has gained the upper hand in the fight and tells him that, once he kills him, he's going after his young son who is hiding somewhere in the house. Upon hearing this, Hotchner suddenly regains his strength and beats him to death in a fit of rage; when his colleagues arrive, they manage to restrain him, assuring him that he's already dead.
CSI: Catherine Willows was a good example of this in "Lady Heather's Box". Eddie's girlfriend started griping about wanting to save Eddie more than Lindsey, and it was all the team could do to hold Cath back. The girlfriend had taken an injured Eddie and left Lindsey alone, in the car, in an insanely heavy rain, after they'd run off the road into a canal. Because of this, Lindsey nearly drowned.
(After being asked to clarify she left Lindsey alone under those conditions.)
Girlfriend: "So!? It's not my kid!" (cue mama bear Catherine)
Horatio Caine on CSI: Miami and Mac Taylor on CSI NY get the same way if you harm their significant others. Horatio tracked Marisol's killers all the way to South America when she was killed,and when Christine was kidnapped, it was clear that nothing was going to stop Mac from getting her back alive.
Sheppard: "Ronon has some things he wants to take care of first."
McKay: "Are you insane? There's at least twenty-five Wraith down there!"
Teyla: "Also, Ronon appears to be quite angry."
(five minutes later, all the Wraith are dead, mostly at Ronon's hands)
Tommy Oliver flies into this once in Power Rangers Dino Thunder. Zeltrax taunts him with his students' impending deaths at the hands of the episode's extra-strong giant monster. Tommy responds by beating Zeltrax within an inch of his life and then killing the monster with the Brachio Staff's newly-activated powers. Without growing or anything.
Babylon 5: Some idiot makes the mistake of throwing a knife at John Sheridan, who is saved because Delenn throws herself in front of it instead. Sheridan's response is to attempt to kill the being responsible with his bare hands, and he would have succeeded if Security hadn't intervened.
In Farscape, Luxan males are prone to a condition called hyper-rage, a berserker state in which they'll attack anything else male around them without thought for no reason whatsoever, though older Luxans do develop the control to prevent themselves from entering it in the first place. A later episode suggests that Luxan males in this state will assault anyone, even their own spouses, which is why Luxans are never permitted to marry young and must wait until they've learned to control it. This is a particular issue for D'Argo, since his Sebacean wife was nowhere near as durable as a Luxan woman would be, which her Peacekeeper brother was able to use to frame D'Argo for murdering her in a fit of hyper rage after he accidentally killed her himself.
In Breaking Bad, after Jesse connects some dots and comes to the realization that Walter was the one who poisoned Brock, he breaks out of the Heroic BSOD that he had been in for three episodes and storms into Saul Goodman's office, beating a confession out of him at gunpoint, threatening everyone who enters, and finally driving furiously to Walter's house and pouring gasoline over everything.
Vincent in the '80s Beauty and the Beast series is much the same. Do not hurt Catherine; he will go through any obstacle in his way to help her. And he has a mental bond with her.
An episode of Agents of S.H.I.E.L.D. revolves around a piece of Applied Phlebotinum that causes this. The villains-of-the-week, along with two of the heroes, are affected by the weapon and subsequently are filled with intense strength and anger.