Florida drivers; especially Miami. I use my turn signal every time; but I basically have to have ESP of other cars on the road. I drive my car like it's a motorcycle, always looking for a way out or around - because it's so wild here.
Motorcyclists drive like maniacs, not like everyone is going to kill them. They drive way too fast, cut blind corners, weave in and out of close traffic without signaling, they make hazardous passes because they can accelerate fast...yeah, that's why I said they must be the dangerous driver.