In hindsight, I realized it was b/c I hadn't found subjects in high school that really resonated with me (although HS science was cool).
When I got to college I majored in computer science (academics) and discovered paintball (physical/social) and threw myself into both with abandon. I would do my CS homework as soon as it was assigned b/c I just loved solving the problems so much that I couldn't stop myself.
For paintball, it became an obsession that eventually turned into a job after college. Again, it was something I loved so much that it just seemed like a natural thing to work really hard running big tournaments. Why wouldn't I work hard on something that resonated with me so deeply.
This reminds me of a quote from Joe Rogan (who I know is somewhat controversial) that encapsulates this perfectly:
"In high school I thought I couldn't focus. I realized I can't focus on things I don't care about. I can focus for hours on things I'm into."