Why Am I Doing this To Myself?

The question can apply to many things in my life, both past and present. Work, school, friends, women, but in this case I am specifically talking about my decision to adopt, what is known in the magazines as, a "multi-sport lifestyle". Which means you give up a lot of your free time to train to do triathlons. So I have spent some time thinking why I have adopted the "hobby" of multi-sport racing (triathlon\duathlon). I have been thinking about the "why" because I have been working out everyday for the last two weeks. Some times I don't feel like it. I just want to go home after work and veg on the couch, but I don't. I go and do my workout, most of the time I feel better for doing it.
Part of the reason I branched off (or returned to, since I was doing these activities semi-regularly about 15 years ago) into swimming and biking is that I was bored with just running. I also did not feel like I was getting into better shape just running. I think combining the three things has helped me get in better shape overall.
After the first race, I fell in love with the feeling I got racing, before, during, and after.

The racing aspect fills something in me that is missing.

I think the feeling from racing is the biggest thing. Whenever I get down about training, I think about racing, and it helps to motivate me.

I think the best I can hope for, the best, is probably top 5 in my age group. So racing isn't about being the best against other people. It is about challenging myself and trying to do better each time I go out. If not the whole race, then the swim, or the bike, or the run, or transition.