It's the reason Andre Agassi, winner of every major tennis title, now hates the game. It may also be why Baseball Hall of Famer Mickey Mantle wet his bed up to age 16. Sports parents can guide their children to greatness -- or go too far and push them over the brink.
What would you do if you heard a parent cross the line and berate a young skater for failing to live up to expectations on the ice?
That's the scenario played out before the hidden cameras of ABC News' "What Would You Do?" at the E.J. Murray Memorial Skating Center in Yonkers, N.Y. Actors were hired to play an overbearing skating mom and her daughter, Olivia, who is actually a real-life skating champ.
As Olivia twirled on the ice, the nightmare mom pounded on the rink's glass wall and screamed at her. "Ugh! Olivia! That's not a champion! That's pathetic! That is absolutely pathetic."
Passersby immediately took notice and watched as she ordered Olivia off the ice to scold her.
"This is embarrassing. Unless you go out there and you skate harder and skate faster than I've ever seen you skate, I'm not doing this any more," snapped the skating mom, who turned on her heel and walked off in a huff.
Immediately, a woman watching the scene came over to comfort the upset girl. "Are you all right? You're just mad at yourself because you didn't skate well?" the woman asked.
Olivia's pushy mother returned and sent the sobbing athlete back on the ice. Standing at the side of the rink, the adults began talking and the woman, who turned out to be a skating coach, asked whether the demanding observer was coaching the teenager.
"No, I'm her mother," the actor said.
"If you're her mom -- as a mom and as a coach -- you need to separate the two and remove yourself. That's what I would tell you if I was her coach," the woman said. "Let her help herself. You can probably do more damage than you realize."
Over-the-top parents sometimes suffer from "frustrated jock syndrome" and desperately hope their children will secure the titles and championships that they dreamed of but failed to win themselves as young athletes, said Frank Smoll, professor of psychology and co-director of Youth Enrichment in Sports at the University of Washington.
"It's reverse dependency," said Smoll. "Normally children are dependent on their parent for own self worth. When a parent over-identifies with their kid so it's no longer Johnny playing the sport, it's an extension of the parent ego. It's the frustrated jock syndrome, the father or mother living through the child to accomplish the goals they were never able to achieve themselves."
Other times parents misguidedly view sports as a route to a college scholarship for their child, and invest enormous amounts of time and money to pave the way.
Rose Malara, a coach for 26 years, told ABC News, "The more money invested, the more time invested, many of the parents come down very hard on their children. Parents want a return on that investment, so they run the risk of crossing the line when they push their child to work and succeed."