Sports and musical instruments - if you can keep them motivated/interested, the results of focused practice can’t be ignored.
To some extent I only realized this late in life myself. I don’t play a musical instrument, schoolwork through undergraduate never required really hard work and as an athlete I was a lackluster football player who never really put in the time to get better. But as an adult, computer programming and crossword puzzles were things which I applied myself to and was astonished to see how much better I could get at them by putting in the time and effort. (That being said I am an awful teacher - as an autodidact myself, I often - unfairly - feel that others aren’t putting enough effort in.)
To some extent I only realized this late in life myself. I don’t play a musical instrument, schoolwork through undergraduate never required really hard work and as an athlete I was a lackluster football player who never really put in the time to get better. But as an adult, computer programming and crossword puzzles were things which I applied myself to and was astonished to see how much better I could get at them by putting in the time and effort. (That being said I am an awful teacher - as an autodidact myself, I often - unfairly - feel that others aren’t putting enough effort in.)