I biked in a busy city grid from 15-55 years of age. I didn't give motorists three feet, and I didn't get three feet. So long as they don't hit me, I'm fine with close passes at speeds below 35 mph - which is the case on almost every street I use. I don't think it's even possible to give me three feet much of the time unless I ride against the curb or in the door zone. I expected close passes and my expectations were met daily.