I could drive to work in under 20 minutes and use very little gas. But my job subsidizes my public transit 100% and parking downtown costs an arm and a leg. So I use the hell out of public transit. I walk 20 minutes to the train stop and ride for 10. The walk is great exercise. All in all, I would be a fool not to use public transit.
Fortunately I live in one of the few US cities that really does it well (Portland, OR), and it's intimidating at first but you soon realize that all of the horror stories you hear from people that have driven all their lives are grossly exaggerated. You'd think the train would be full of people being stabbed and vomited on, and sketchy guys carrying TV's that they just stole from that affluent neighborhood they just opened a new stop near. No. It's mostly just tired people going to or from work, 80% of them with their faces buried in their phones. A few tourists. Some teenagers on their way to the park or the mall. Every now and then there will be a stinky guy or a loud phone talker or a screaming baby, or some guy (illegally) trying to sell you incense sticks. That's about the extent of it, and if it's too crowded, most of the time you can wait for the next one and it will be near empty.
At my previous two jobs I drove every day and eschewed public transit. Here it's gotten so that I actually dread the day I have to commute by car again and feel sorry for the people that have to. The next time I move, proximity to public transit will be very high on my list, probably above access to fast broadband.