I'd like to think so, Patz, but in all honesty I doubt it. The pros are obvious, in terms of doing something constructive for the environment, because I'd be doing my bit to save on energy and fuel consumption and help to lessen pollution from auto emissions. But as someone else has already said, I like the privacy and comfort of my car. I enjoy that quiet time to reflect, or catch up on the day's news or listen to some of my favourite music. I've also experienced public transportation many times in the past, especially during my student days, and I really grew to detest the lack of cleanliness and basic civility often encountered on buses and subway cars.
That said, I'm just going to be painfully honest in answering these queries of yours... Okay, already covered questions 2 and 3... Yes, I've occasionally used mass transit owing to weather of vehicular concerns, and my impression remains unaltered. Consistent encounters with rude and obnoxious people, unclean (or non-existent) seating and other amenities, delays and other scheduling issues, it's just a mess... And no, I could not make a habit out of it because the service is just so unpleasant and unreliable.
I should add, however, that I loved Japan's mass transit system and regularly took trains there. The US is definitely lagging in this area compared to other western and industrialized nations. Frankly, it's an embarrassment and says a lot about our misplaced priorities.