I love sharing my commute with my toddler son. Sometimes we talk, sometimes we don't. I love the sights, sounds, smells we experience together. Cruising down a hill and hearing him say "weeeee" makes me want to do it too. I know I won't have this time forever, so I cherish it.
Other than that, a bike commute is really the best way for me to wake up and start my day. When I was working an office job, I always relished the fact that I got to the office feeling invigorated by the fresh air instead of stressed from being in my car and fighting for a parking space.