Music
Years ago my first concert had a formative impact on the rest of my life. It led to my first piano lesson, a chance electronic music course in middle school, and some graduate research on hearing aids. It's always been a bit of an oddball hobby within my family, but watching my niece grow to love music (and live music) the same way I do has been exciting to watch.
I don't spend nearly as much time as I'd like doing it, but I still love to listen to and play music. It's genuinely cathartic. Through the piano will always be my strong suit, I've recently made a very real effort to learn the guitar as well.