Unlike in the UK, MOST drivers in the US have no idea where the fenders of their car are, or how much clearance they have. So even if I'm RIGHT on the edge of the road on my bike, and cutting straight along with a steady cadence, no wobbling ... sometimes a car or truck will come up behind me, and won't pass even if there's plenty of room to pass me even without crossing the center line of the road. Then FINALLY, they will swing ALL the way out into the other lane, pedal to the floor, and wave a salute and a "Get that f***** toy off the road!" (read "MY road".
Not much of a bicycle culture here. No village church minister, postman, county nurse, etc EVER rode a bicycle anywhere here, so, much like motorcycles, people in cars think they're just toys ...