My oldest daughter is still haunted by a couple pitches. She says she will always remember certain losses. Championships. One pitch away from winning, a strike down the middle that didn't get called and a passed ball that caused a loss.
At the age of twelve, DD1 could have felt she "lost" a LL Tournament game on a catcher's interference call. The Bases were loaded, full count, two outs, game tied in 7th inning. She caught the pitch and framed it, then batter swung and knocked the glove off her hand with the ball still in it. Batter advanced, run scored and game over, we go home instead of to state tournament.
Sure she felt terrible, but she never got another CI call again.
She hates losing, but she also found a way to make a positive out of the experience.