Sykk, you came on a board of adult webmasters with an exercise question?!?! :P
Seriously though, one problem (besides just the regular muscle pain, which was plenty) I had every time I started out to exercise was overdoing it. (Which is why it doesn't happen to frequently.)
It's like a car, and I get enough momentum to finally go, get off my ass and workout, and when I do the car's going to fast, rather I am. I've built up so much momentem to get to FINALLY doing something, I go hit it too hard, do too much and end up hurting myself .. and I mean hurting myself GOOD. Pulling too much weight, doing too many reps, whatever, and something always gives and ends up killing me for a month or more.
I so badly want to get into excercising and such but everything time I think about I remember all the other failed (and pained) times. Always happened in the first week or two when I start. If I could just get up the momentum to do it, then be able to hit the breaks or lower my gears and take it carefully I'd be happy.
Who knows, maybe now that I'm older and wiser (and older and slower!) maybe next time I'll actually take it easy when I start. I was thinking maybe the personal trainer route would be the best way (so I don't over do it) but after reading this thread that doesn't sound like such a viable option either.