When people slow down, then they start to turn, and then they turn on their signal halfway on through the turn. It's like...what the hell was the point of that? It annoys me because if they were going to use the signal, at least do it properly and warn drivers behind you of the turn ahead of time, but during the turn?

Another annoyance is when people go waaaay too slow under the speed limit when conditions are perfectly fine. This one guy was going 40 in a 60 zone and I must say, that's a dangerous thing to be doing. He was going downhill, so someone going 60 could've came over the peak of the hill and not seen him in time.