This always baffled me. Until I started thinking about it.
I do the same thing. Sure, it manifests differently. But I'm all or nothing too. When I decide to do something, I want to do it with passion and knowledge. It's all or nothing.
About two years ago, I decided to start running. Being 100% full on all the time, a year later I was running a full marathon. This year, I've been training for my second marathon. And now, in order to get the full experience of being a "real" athlete. . . I've injured myself.
I'll be seeing an orthopedic sports doctor tomorrow afternoon. My PCP thinks that it's probably a stress fracture or a tendon problem. The former will put me out for the marathon this year. The other we might be able to work through.
For now, I'm allowed to run "until it hurts." Which seems to be about 3 miles currently. Ugh. On to the rowing machine, I guess.