My biggest frustration is people who just won't get the Hell out of their own way! I'm not talking about speeding either - I drive the speed limit and am not particularly fond of those who do not, but will generally take speeders over slowpokes as the former are "usually" paying attention.
FFS, get moving, learn how to turn right on red, learn how to turn right when you have your own fucking lane to turn into and quit stopping. I'm convinced that more accidents are caused by brake pedals than were ever caused by gas pedals. And when you have the right of way, TAKE IT - don't waste everybody's time by "being nice". You don't have to wait until the road is completely clear to the town 20 miles down the road before going either.
With all that said, I'll take Florida drivers over the idiots in California any time! About the only thing Florida drivers consistently suck at is the afore mentioned right turn into their own lane - about half of them needlessly stop for nothing, didn't see that much in Cali. I always have one foot poised above the brake and one hand poised above the horn when following someone into that situation - and I'm not the only one! Left turns at lights without a dedicated left signal aren't the greatest in Fla either, but that's due to a difference in the applicable laws.