Paralysis by Analysis

It's the final quarter. The game is still too close to call. The clock is counting down. There are seconds to go. You have the ball. It's all up to you. And you stand there. And do nothing.

Friend, you just choked.

Any time you're doing something you're accustomed to, something you're good at. Hell, you can be a recognized master in your field, but as soon as the pressure is on, you can choke. It can happen in sports. It can happen on game shows. It can happen in bed.

Expert athletes often talk about getting in "the zone", when they stop thinking about what they're doing it and just do it. This usually leads to nigh balletic performances when they go above and beyond and win the god. Damn. SUPER BOWL.

Choking occurs when, instead of getting in the zone and shutting off the thinking, the expert starts thinking about what he's doing. He starts trying to control everything, trying to account for every last variable. He gets in his head and because there's just too much to think about, he can't do anything. Paralysis by analysis. Similar to the Centipede's Dilemma.

Film

 * 8 Mile: Bunny Rabbit's first time performing on stage leads to him freezing while the crowd chants "Choke! Choke! Choke!".
 * Teen Wolf: The eponymous teen opens the movie at the free throw line, way up in his head. He bounces. He bounces the ball. He bounces. He bounces. He bricks it. He is despised.
 * Bull Durham: Crash's rule #1, "Don't think, it'll only hurt the ballclub."

Live Action TV

 * Psych: "Shawn Gets The Yips"
 * Numbers: Charlie's dad can't understand why the Cal Sci Basketball team is so poor (although Charlie points out, not unreasonably, that it's not really a burning concern for a bunch of science geeks) and convinces Charlie to try to improve them using "Scientific Methods". This only results in increasing frustration for Charlie as his methods fail to achieve anything. Ultimately, they only win

Western Animation

 * My Little Pony: Friendship Is Magic: Rainbow Dash has this issue, particularly when her idols, the Wonderbolts, are involved. For instance, in "Sonic Rainboom", she enters into a big stunt flying competition for which the Wonderbolts are judges. However, her inability to pull off the titular move a second time (after pulling it off once as a young filly) while practicing gives her pause for thought, which quickly snowballs into panic, and eventually leaves her practically catatonic with fear.

Real Life

 * Ken Jennings, the winningest guy ever to win at Jeopardy once told an interviewer that the question he was most embarrassed about getting wrong was because he knew the answer. And he knew that he knew the answer. He just couldn't remember the answer, because he'd never sat down and studied the poem like he did with everything else. Because it was his father's favorite poem: The Jabberwock.
 * Professional Greg Norman blew it out of the water for three days at the 1996 U.S. Master's. Then he tanked on the last day and finished five shots out of first (And That's Terrible).
 * This article describes and explains the phenomenon, and is also the Trope Namer. It's more complex and varied than simple Paralysis by Analysis. Sometimes it's a desire to avert stereotypes (an Asian kid flunking math, a black kid who's bad at sports, a boy who really doesn't want to follow in the footsteps of a domineering father who he's actually a lot like). Sometimes it's because of stereotypes (an asian kid being bad at sports, a black kid or a girl bad at math and science). There are a lot of ways to drive yourself to undeserved failure.
 * This is ESPN's list of the ten worst chokes of sports history.
 * This list focuses on golf.
 * The other wiki has a list organized by sport.