What things do you have to have just so?

[Ghoulish Delight]

Video games.

More-so back in the era of games you couldn't save, so each time you sat down was a complete game (win or lose). If it was a game I owned and got good at, I'd eventually settle on some optimal, or particularly fun, path through the game and would often restart the game if I messed up said path.

There was at least one Nintendo game that I knew by rote so well that I could literally start the game, flip the TV input back to TV and play chunks of it blind. Bases Loaded. There a few pitchers that had pitches the computer couldn't hit. I'd flip over to TV, throw 9 strikes blind, then flip back to play offense.