I enjoy it.

For the most part, I just ride for the enjoyment and for exercise. I tend to ride out of town for a ways and take in the sights, sounds, and smells that I'd otherwise drive past without ever noticing. Take a turn down a different road whenever the whim strikes, just to see and experience what's there. Feel the sun and the wind instead of seeing it through glass. And it's good exercise without feeling like work.

Another reason I bike... I #$&%ing hate running.