I commute (everywhere) by bike:

Because it's faster than fighting traffic in a car.

Because today I passed a lineup of 15 cars inching down the street (each way) behind a garbage truck. Not enough room for anyone to get by going either direction - but room for lil' old me!

Because when I get home, I don't care one bit about anything (a bad day at work, the rain, traffic, chores or bills I haven't done yet, etc) except dinner (and maybe a shower).

Because my co-worker the road cyclist calls me hardcore for being a commuter!

Because sometimes I can keep up with the the messengers (who really are hardcore) through downtown.