I've lived in the US for over 60 years and never experienced what you are talking about. Oh, except when visiting NYC and LA.

There are plenty of pleasant, laid back places to live in the US, you just haven't lived there. It's a big country. I guarantee you taxi drivers aren't screaming at each other in Anaconda, Montana or Calais, ME. (I'm not entirely sure they have taxis.)

I lived in London for six months in college. I loved it, but I found it enormously stressful and the people, in general, were uptight, unfriendly and judgmental. (There were exceptions, of course.) That was my experience, but I can't say the whole of Great Britain or even the whole of London is like that because I didn't live everywhere.