This is to give cred to the OP, not discredit, but I don't think this conversation is ever complete without experiences people have had outside of the US.
I've ridden in Europe (not UK), and despite the bad apple or two it is lightyears better there.
It's even better driving, to me. Commercial drivers seem infinitely more responsible. People in the countries that follow cycling as a sport are very friendly to riders.
Penalties in the US for traffic crime just aren't sufficient as deterrents. We're too wealthy a country for most infractions to really make you think about not doing it, prison or fines.