We’ll admit it: there’s a ton of pressure on professional athletes. These men and women are asked to perform flawlessly in front of millions of people, so when one of them makes an error in the field or throws the ball away or drops an easy touchdown, we tend to forgive and forget and move on. But sometimes, a player has a brain fart so incredibly embarrassing and memorable that it defines the rest of his career.

Here are a few examples of mind-boggling mental lapses:

Chris Webber Calls a Time-Out He Doesn't Have

As a member of the “Fab Five,” Chris Webber helped the University of Michigan to a pair of NCAA championship-game appearances, but he’ll always be remembered for his infamous mental lapse in the 1993 finals. Trailing North Carolina by two points with just 15 seconds remaining, the Wolverines turned to their star player to pull out a victory. Webber responded by dribbling himself into a corner, panicking and calling a time-out that Michigan didn’t have. The error resulted in a technical foul and effectively handed the Tar Heels the national title.

Steve Lyons Takes His Pants Off at First Base

Ever had that nightmare where you're in class and everyone's laughing at you because you're naked? It's terrifying, sure, but man, what a relief it is when you wake up and realize it was just a dream. In the case of former Chicago White Sox utility player Steve "Psycho" Lyons, though, tens of thousands of people really did watch him take his pants off. His moment of realization—"OH MY GOD I JUST TOOK MY PANTS OFF IN FRONT OF ALL THESE PEOPLE!"—is priceless.

Marshall Runs The Wrong Way

Aside from the mockery, the worst part about making a mental mistake in professional sports is that it can overshadow an otherwise stellar career. Former Vikings defensive end Jim Marshall, the one-time owner of several NFL records, knows this all too well. In 1964 game against the San Francisco Giants, Marshall picked up a fumble and ran the ball 66 yards…into the wrong end zone. Poor Jim threw the ball into the air and celebrated wildly, unaware that he had just made one of the most embarrassing plays in the history of pro football. The mistake cost the Vikings a safety and earned Marshall some unwanted (and undying) notoriety.

Assorted Leon Lett Hijinks

Leon Lett was a crucial part of the 1990s Dallas Cowboys Super Bowl dynasty, but he’ll be remembered more for a pair of head-scratching plays than for his football skill. First came his infamous goof during the Cowboys’ 52-17 thrashing of the Buffalo Bills in Super Bowl XXVII. Lett had recovered a fumble and was about to score when he stuck the football out to his side and began to celebrate. Buffalo receiver Don Beebe, who had been chasing Lett, stripped the ball and denied the touchdown, delivering Lett his first major dose of embarrassment.

The very next season, the Cowboys held a 14-13 led over the Miami Dolphins on Thanksgiving with 15 seconds to go. Dallas managed to block Miami’s last-second field goal, which should have secured a win. Instead, Lett tried to pick the ball up and score, only to accidentally kick it back to the Dolphins. Miami completed a second field-goal attempt, costing Dallas a win and Lett the remainder of his dignity.

Jeremy Giambi Decides Sliding Isn't For Him

The New York Yankees of the late 1990s and early 2000s were certainly good enough to win without any help, but a little luck never hurts. That’s the only way to explain Derek Jeter’s incredible flip play during the 2001 ALCS. The Oakland A’s were one game away from clinching the series when Terrance Long ripped a ball down the first-base line. Jeremy Giambi rounded third and should have scored easily, but he chose that moment to abandon the baseball fundamental known as sliding. Jeter cut off the errant relay throw from the outfield and flipped the ball to Jorge Posada, who immediately tagged a baffled Giambi out at home, preserving a one-run lead. The Yankees went on to win the series, and Giambi gave us another reason to ridicule his career.