I haven't started commuting yet (just got my commuting bike yesterday actually), but I am already used to people getting mad at me on the road. I have an 89 Chevy pickup that is, uhm, not a vehicle known for fuel economy. Since I can't afford to get another car, when I have to drive the truck I drive it like a grandma, I accelerate real slow, generally go under the speed limit 5-10 MPH, etc, to save on gas (I do all the other stuff too, keep it tuned up, check tire pressure, etc). I have people tailgating constantly, and the really angry ones sometimes flashing their lights or honking when there is no place for me to go to let them pass (I don't do this in fast/passing lane on expressway) then when they can pass they roar past me a gazillion miles per hour flipping me the bird, then slam on their brakes to stop at the traffic light, then light 'em up to race to the next traffic light to slam on their brakes, repeat ad nauseam. Hey, the less I use my brakes the less I am accelerating and wasting gas I figure. Its amazing how stupid and wasteful some drivers are.