The main "lesson" I have learned is that I can change (at least, in some ways) if I work on things, and that working on things is good and important. This sounds obvious but I don't think I really knew it before, I felt like any kind of work was just tiring and time-consuming and if I wasn't going to be the best or perfect anyway, then what was the point? I have really expanded into new areas/activities over the last couple years because I'm much more willing to give things some effort than I used to be.