in the city here, riders generally don't follow traffic laws that well, and at the same time, other drivers aren't very considerate to them (as in, unsafe - opening doors, pinching riders, honking horns).
The city in turn made bike lanes on several of the roads that are both off limits to drivers and (in some cases) physically separated by things that you can run over (like permanent vertical road cones) and probably have to pay to replace.
When I moved here, I learned of the bike messengers:
* single speed fixies or with regular hubs (but no multi-gear cassettes)
* rail thin folks, ride in traffic without regard for themselves at all (you eventually learn to drive and ignore them - they are pros and already know what dumb or smart things you could do , you won't hit them, they're a step ahead of you mentally)
* averse to taking showers - which you find out when you have to sign for a package
Total subculture, I thought it was interesting (poor pay), though.
They seem to have disappeared thanks to digital transmission of documents and the elimination of physical wet signature requirements on a lot of regulatory compliance stuff.
When I was riding recreationally, I lived near several loops that were heavy bike and run traffic and little in terms of cars. It was a real luxury (large loop was 5 miles with designated bike and pedestrian space - never endangered by cars, but sometimes issues with peds feeling special and walking opposite side of the road with headphones on and in the bike lanes "ON YOUR LEFT" often heard only when close enough to yell over what they were listening to, and not a non-zero chance that they would jump to the left when they finally heard you). Biking stopped when I didn't live close enough to the loop to ride on it.
A couple of rides outside of designated bike areas (including rural, in one case getting brushed by a passing car mirror) and the death of a coworker's relative and another acquaintance - one due to a drunk driver mid-day, and the other an elderly driver - cured me of the idea of just riding anywhere.