It happened when I was 10 and it's been mostly downhill ever since.
I was playing rec league baseball. We were in an important game, maybe one of the final games of the season.
I came up late in the game with 2 outs and the bases loaded. I don't remember the score at the time but it was close.
I hit the ball further than I can ever remember having hit before. It was an opposite field shot that went way over the right fielder's head.
Grand slam!