What Are Your Driving Pet Peeves? [SURVEY]

We talked about roundabouts and merging with the zipper method this morning. What are your biggest driving pet peeves? It bugs me when people don't speed up to merge into traffic -- or worse, when someone in the right lane slams on their brakes to let someone merging in! Or how about when people take advantage of the zipper effect to try to "cut" in line! What about you?