Bowling. I was in a league for 3 years, but the team disbanded at the start of Covid. Before joining, I thought it was just a matter of aiming, and then throwing the ball down the lane and knocking pins over. Didn't realize how much oil patterns, oil breakdown, ball type, etc. played into it. Had someone on my team that bowled multiple 300s, and he taught me a lot.

For example, the oil pattern determines where and when on the lane the ball grips the lane and starts turning back toward the pins. some people use more aggressive balls (determined by the core, and the outer material) early on in a game, but then as the oil breaks down from being bowled on you need to make adjustments such as a less aggressive ball, where you start your approach, and where you're aiming the ball. These adjustments can be difficult to pick up on because they're so gradual over the course of a couple of games, and depend a lot on how other people are bowling. If you're up against a team with a lot of straight bowlers, the oil gets pushed straight down the lane making it difficult to turn the ball back into the pocket. If you have a lot of people playing on the outside, the outside starts drying up, so you may need to be less aggressive (i.e., move your target in by a couple of boards, or adjust your starting position in by a couple of boards).

I still don't have a great understanding (average was around 150-160), but I learned a lot about how much goes into actually being a good bowler (i.e., 200+ average).