Inspired by the other thread let's ask, is your bike commute faster or slower than public transit?
I know for me, this was a major factor to start commuting by bicycle.
I couldn't afford a second car and my wife needed the car to be with our new born daughter at the hospital along with our 3 year old son. I checked the bus schedule and it would take me an hour to arrive at work. Even at my snail's pace, the bicycle took me 45 minutes. Add in that the bus fare would pay for a new bicycle each year and the choice was clear.