It made sense for America to become a car culture. Prior to the automobile most people never went very far from home. There was a time in this country your whole world was your town. Anything beyond it was something you'd dream of. A lot of people didn't really get to travel much. Of course there were the pioneers but once they settled somewhere they pretty much stayed there. The railroad made a difference as well. But ultimately, due to the nation's size and culture most people stayed very close to home.
Then along came Henry Ford and the Model T. It changed everything. Now cars were not toys for the rich. Now people could travel further from home. This meant you could go further for a job. And so we ended up with commuting. And it also meant we had our own natural tourism industry. Thanks to the car the sites and attractions America has became accessible to people. So was born the great American road trip. Something we still love here. Though it's getting more and more expensive.
The car really changed our country. To America mass transit is anathema to the spirit of our car culture. Americans always loved independence. The car in many ways is woven into that you see. If you own a car you're independent. Don't like your town? Load up the car and drive to a new one. Don't like this job? There's a better one for you 100 miles away. Bored and nothing to do? Hop in the car for a spin. Go on a weekend road trip. Hell, this is even reflected in our RV culture. What could be better than having a home you can drive?
Mass transit has its perks obviously. And is great for heavily urbanized areas. But overall it really is not an "American" thing. Still, I do like the idea of transcontinental rail travel. It must be nice to climb aboard a train and go from one end of the nation to the other.
The worst is bus travel. Be it the "government cheese" school bus or a charter bus. Long trips in a bus are always a miserable experience!