[Mark]

3) Drivers who honk at bikers as if they oughtn't to be on the road.

Mine is kinda a bit of the opposite - bikers who plop themselves in the middle of the road like they own it, especially if there's already a designated bike lane avaliable for them (seriously, "sharing" the road doesn't mean bike riders get total control - for both our safties, stay in your own lane!).

Also, runners/joggers who insist on running/jogging in the road when there's a perfectly good sidewalk available.