Chess
When I was young, I got into chess. My dad had a miniature electronic chess set he would play against a computer. Of course, I thought that was so cool, and wanted to learn myself. So he taught me all the moves.
I became good enough that I could beat 12th grade high schoolers when I was in 4th grade. I entered a chess tournament at MOSI and won first place two different times. I remember being so surprised, because I didn’t have self-confidence. At the MOSI “tryouts” where they were showcasing the upcoming tournaments, I was nervous, and lost to the famous 4-move checkmate. And then during one tournament, my opponent was some cocky kid who seemed really good. (Turned out in one of our matches, he tried making up rules for how to draw, but I was well-versed with all the chess rules and didn’t let him get by with it.)
I would practice with the chess set. It had 8 levels of difficulty. I remember beating level 7 one time. I had discovered a certain set of moves that it wasn’t smart enough to overcome. This happened while waiting with my parents in a Carmax office. But level 7 took so long to “think” and make a move (several minutes), so I didn’t enjoy playing it. Level 8 seemed to never make moves.
I rarely beat my dad. It got to the point where I became bored with waiting for opponent’s moves.
In college, after learning how to play shogi and becoming pretty decent at that, my chess skill went down. I would get confused with pawn moves. In shogi, they attack forward, and I got so used to that, I would make simple mistakes in chess where they attack diagonally. My current self would probably lose badly if I were to go back in a time machine and play chess against my middle school self.