I live, and bike commute year round, in a bike-friendly city (Portland, OR). I don't attribute my pleasant ride to bike infrastructure but rather to the work the city did in the late 60's to fight urban sprawl with a thing called the "urban growth boundary." It stopped farmland around the city from being turned into subdivisions which forced people to fill in and maintain the older neighborhoods close to downtown. My 5 mile commute to downtown is through quiet, nice neighborhood streets, no special bike infrastructure needed.
Note that Portland is investing in bike infrastructure now, and it makes certain crossings easier, but I think the bikers came first, not the infrastructure.