Fear can be a good motivator. Maybe someone is afraid of losing something good, or gaining something bad. Whatever it is, it can push someone to fight harder than ever before. This isn't a trope about Facing Your Fears and overcoming them, this is about using fear as a catalyst to do the difficult or impossible.
This is common in preaching (of the religious sort especially) and propaganda, in that they aim to motivate whoever listens, through fear of something, to follow the preaching/propaganda. See also Appeal to Fear; related is Appeal to Force. (Compare Hobbes Was Right, contrast Machiavelli Was Wrong.)
Related is Cowardly Lion, who manages to do epic deeds despite their fears—here, characters do epic deeds because of their fears—and Die or Fly, when they unlock abilities by facing a stressful, and at times frightful, moment. See also I Control My Minions Through...; one option is "Fear". This is the number-one motivation of the Dirty Coward and Lovable Coward.
- In Naruto, Sasuke activated his Sharingan for the first time when he was scared out of his wits due to Itachi killing their family.
- Usopp in One Piece gets easily scared by a lot of things, especially his group's enemies... but the fear of losing his friends/allies is greater for him that it motivates him to fight the enemies, although in his own cowardly way.
- Fist of the North Star: Raoh explains this as how he keeps his army in check. When facing against Shuren's army, he explains that their loyalty comes not from being a good leader or being an inspirational speaker, but because the only other option is death by his hand. And considering that Raoh is a behemoth of a man who can make people explode with a finger while riding an equally massive horse, he pretty much has all the motivation his troops need to throw themselves to their deaths at the hands of the enemy.
- The Black Dog knights in Berserk are made up of the worst criminal scum in Midland, so one could imagine just how much discipline would be a problem ...except it's not, as the leader of the unit, Wyald, is both an Apostle and one of the most gleefully sadistic monsters of the setting (which given the standards of the Berserk-verse is really saying something) and he enforces his will through his incredible power and cruelty. As such, when pursuing the Band of the Hawk while the latter attempt to flee Midland, the Black Dog knights throw themselves heedlessly into whatever booby traps and ambushes the Hawks throw at them to slow them down, not out of fearlessness but out of the sheer terror that Wyald inspires in them.
- Asterix and the Normans' plot starts when the Normans take the expression "Fear lent him wings" literally and decide they'd like to know how to fly. Being Vikings, they also literally don't know what fear is, and embark to find the biggest coward who will teach them. They eventually learn the feeling when they're threatened with listening to another of Cacofonix's songs.
- Disney Mouse and Duck Comics
- There's a Donald Duck story where he needs to win a bicycle race, but his nephews' Training From Hell was so horrible (bathing in ice water at 5 AM, attacked by bees etc) that he falls asleep at the start line even when the gun is fired. Scrooge hides in the bushes and makes a loud buzzing sound, which not only wakes Donald up, but supercharges him to the point that he careens past the other racers without even realizing it.
- In an early Mickey Mouse comic, Mickey is scammed into buying a horse named Tanglefoot, thinking it's a top-tier racehorse who will let him win the upcoming jockey race. But initially Tanglefoot appears to be utterly useless and untalented... until Mickey discovers Tanglefoot is afraid of bees. Thus he mimics the sound of a bee swarm in the horse's ear to make it think it's being chased and thus dash away at top speed.
- In The Outside, this trope is part of the reason why Satsuki does a lot of what she does, as, in being so agoraphobic, she forbids Ryuuko from going outside and enforces her rules with Logical Fallacies, however, the most telling example of this trope is when the others find a picture of a baby Ryuuko with Soichiro playing in the snow, Shiro putting it best:
"Yes, but she did what she did and we can't go back and change it. I can't say for certain as to why she'd keep it to herself but I could say that she did it for what, to her, felt like protection. She wanted to protect you and, so, in her grief, she kept the picture from you, especially since she already had it ingrained that the outside world was dangerous."
- Marcus Flint in The Rigel Black Chronicles promises his Quidditch team that they'll win, "because if we don't I'll have you practicing in sandstorms for a week straight, complete with blistering heat and swarms of sand fleas. Any questions?"
- In The Dark Knight Rises, Bruce tries making the jump out of the Pit several times. His first few tries are with the rope attached to prevent him from falling to his death. After talking with a prisoner who tells him that Bruce's lack of the fear of death makes him weak, not strong, Bruce tries the jump once more without the rope, in full fear of falling... He makes it.
- Tremors. Crazy Survivalist Burt Gummer gives annoying teen Melvin Plug a handgun to shoot the Graboids with as they run to the safety of a rock outcropping and after he continuously asks for one... and Melvin finds out the hard way that the gun was unloaded, forcing him to run faster. Which is exactly what Burt wanted him to do.
- Doctor Indiana Jones routinely has adventures involving life-threatening crises; it's this mortal fear that compels him to develop those marvelous Indy Ploys.
- Once Upon a Time in the West has Frank (Henry Fonda) quipping to his employer, the rail baron Mr. Morton, that people are more likely sell the land to them if they're properly scared and that 'people scare better when they're dying.'
- Inverted in Doctor Strange (2016), where The Ancient One claims that fear of failure has actually held Strange back (he claims his fear of failure is the reason for all his successes) rather than made him great, because it has kept him focused on himself instead of others. We see that before his accident when he refuses a patient because they're implied to be a hopeless case and taking it would damage his well-known success rate.
- In the Chronicles of Narnia novel The Horse and His Boy, the horses Bree and Hwin are too tired from their voyage to outrace Prince Rabadash's army, and the author notes that they were pushing themselves only as far as they thought they could. Suddenly, a lion attacks them and the horses get a burst of speed from their fear to escape the predator. The lion is later revealed to have been Aslan, whose attack was a Batman Gambit that he knew would make them go faster.
- In Snow Crash by Neal Stephenson, the protagonist Hiro faces off against a beast of a man named Raven who fights with glass knives sharpened to only a single molecule wide, and also uses them to create deadly spears out of bamboo. Hiro is saved by only a stroke of luck, and later is up until three in the morning training with his katanas, and "floating around on an ocean of generalized terror." His panic inspired intense training ultimately saves his life later and allows him to defeat Raven and stop the Snow Crash virus.
- In Scrubs, when asked to give a pep rally to JD's residents, Dr. Cox deliberately tries to frighten them by telling the residents it's just a matter of time until they kill someone. Later, when talking with JD who is shaken by the experience, Cox tells him that a little fear is good for a doctor. It keeps you on your toes, or as he put it, "stops you from becoming a crappy doctor".
- Played for laughs in the Stargate SG-1 episode "The Pegasus Project," a crossover with Stargate Atlantis. Rodney McKay from Atlantis has a well-known citrus allergy. When SG-1 needs some calculations five minutes ago, Col. Mitchell threatens him with a lemon Col. Sheppard gave him for exactly that purpose, and Rodney provides the results very quickly.
- In the Doctor Who episode Listen, The Doctor tells a young boy about the nature of fear:
The Doctor: Let me tell you about scared. Your heart is beating so hard I can feel it through your hands. There's so much blood and oxygen pumping through your brain it's like rocket fuel. Right now you could run faster and you can fight harder. You can jump higher than ever in your life and you are so alert it's like you can slow down time. What's wrong with scared? Scared is a superpower! Your superpower! There is danger in this room. And guess what? It's you.
- Breaking Bad: Fear motivates a lot of Walter White's actions through the series. Partially, fear of dying and leaving nothing behind for his family gets him into the meth business into the first place. Fear of himself and his family being murdered causes him to conspire to kill Gus Fring, even though he had the chance to walk away clean.
- Saved by the Bell has a Played for Laughs example. While engaged in a prank war with a rival high school, Zack, Slater, and Screech have a brainstorming session for a prank. Slater suggests filling their swimming pool with snapping turtles, but Zack shoots him down saying "The last time we did that, their swim team set a world record."
- Star Trek: Voyager. A Discussed Trope in "The Thaw", where the Monster of the Week is the personification of fear, created from the unconscious fears of several people trapped in a Lotus-Eater Machine.
- Traveller board game Azhanti High Lightning. One of the scenarios, "Dead Ship", takes place in a wrecked ship floating in an ammonia sea on the surface of a gas giant planet. Adventurers salvaging the ship are attacked by "blobs" that live in the ammonia. Because of the high gravity of the gas giant the adventurers may normally not move faster than a walk. However, characters who panic at the sight of the blobs may move at a trot despite the high gravity.
- Warhammer 40,000: Commissars are memetically famous for ruling through fear: the slightest sign of Lacking Moral Fibre can and will be interpreted as cowardice of the most base and irredeemable kind, resulting in immediate execution (and a considerable increase in morale among the survivors).
- In Max Payne, Vinnie Gognitti is shot and in terror of his pursuer manages to run across several rooftops and jump onto a train to escape, bleeding all the while, leading Max to speculate that it's fear that gives men wings.
- Late in Pillars of Eternity, when Iovara asks the Watcher why their original incarnation betrayed her, one of the possible answers is that they were scared senseless of what the Big Bad would do to them if they didn't. This answer actually relieves her greatly, since it confirms that it weren't her teachings that turned them away.
- Dawn of War: Squads with zero morale move faster but take more melee damage.
- Truth in Television: response to a fear stimulus can activate adrenaline, allowing someone to react quicker, and accomplish physical feats they would not have been able to pull off before.
- North Korea. While not the only tinpot dictatorship in history or even currently in existence, it is certainly one of the worst. This trope pretty much applies to the whole populace. The whole situation is usually likened to a giant hostage crisis.
- This is often common advice/techniques for actors. Chris Evans says he bulked up massively in a short period of time for the role of Captain America because he was terrified of letting down people and disappointing fans. Similarly, many actors are often instructed to use their "nervous energy" and deliver a better performance.