Once you get in your first accident you'll realize that safety should be your chief concern.
I wish I had an elevated track that went from my apartment to my office so all I had to do was pedal.
I've been doored and pushed over into traffic by a deaf girl (I spooked her as I was passing and she wheeled around and pushed me over, obviously she didn't hear me say, "on your left").
Knee injuries really, REALLY, hurt. :|