That's basically what I go by - I could care less about someone (not a truck or bus) passing less than 3 feet away if they're only going 5mph faster than I am.

Since I ride to school, I'm typically passed by several school buses, all of which give me the entire lane and wait for the largest gaps in oncoming traffic (they also turn their hazard lights on while doing so; not quite sure why). When a semi truck comes behind me, I either pull off the road or slow down when the truck is passing, since they never wait nearly as long as school bus drivers for gaps.

Based on my definition of getting 'buzzed', i've only been buzzed once - that was when I was a few inches inside a bike lane and someone flew by (without moving over) in the right lane at probably 45mph or so.