Coming home the other day on the bus from an appointment across town that it hadn't been convenient to bike to, I found myself sitting next to a neighbor of mine. I got off the bus at my workplace to pick up my bike, which I had left there, and she continued on home on the bus. I went and got my bike and because it was hot and I was tired, I took a very leisurely, meandering ride home, not riding at nearly my normal pace, but coasting a lot and enjoying the breeze, and not following the bus route but taking back streets through the neighborhood. As I pulled in to my apartment complex, my neighbor was still down the block, just walking up from the bus stop. If I'd been riding at my normal commuting speed I'd have beaten her home by several minutes, but even totally loafing along I made better time. I used to ride the bus to work regularly before I started biking, and getting there by bike is usually a good ten minutes faster (it's just a five-mile distance) and it wholly eliminates the "waiting-for-the-bus" time, so if you count that it saves even more time. I leave later, get there sooner, and feel much better.

My city--Sacramento--has a tolerably decent but sometimes annoying and inefficient bus/train system and I do use it occasionally, but biking is way more fun and better in a hundred ways.