My loves of bike commuting:

#1) Fun and environmentally responsible. Fun factor is the biggest one for me. I actually really enjoy being that crazy late-night biker with all the lights and getup on the road. It's like an adventure every day, especially during the later hours. I also love window-web shopping for bike upgrades (even though I rarely upgrade.)

#2) Convenience - In LA, traffic can get horrendous during rush hour. Parking is equally bad. So bike commuting is a big plus. However, this can be offset by the crush of cars trying to run you over on non-bike friendly streets.

#3) Cost - While it definitely costs a lot less to ride a bike than to drive, I could take the local bus for similar cost. Still, it makes me happy to be using a fixed-cost expense rather than something oil-dependent. I still don't like the cost argument though, as it would mean that you would drive just because you could afford it - which I don't think is valid.

HATES:

1) Having to change out of bike clothes. God I hate this part. I feel like a homeless person when I'm changing from bike clothes to normal clothes in a bathroom.

2) Lack of secure storage for shopping, etc. - Shopping is severely limited by my lack of a trunk to store things. Of course, this comes with the benefit of not buying too much useless stuff!

3) Slow factor - In almost all situations for me, the bike is slower than my car. Even in hellacious LA traffic, I can only beat my car time by minutes. My bike commute is short, so it's not a big deal for me but for me, the car is undoubtedly faster, even with the parking hassle.