Bicyclist who ignore the rules of the road.
Just because you're on a bicycle doesn't mean you can do whatever you want. Bicyclists have the same responsibility as drivers. You need to follow the rules of the road. When there's a stop light or stop sign, you must stop!
I've almost run over a bicyclist before, because he didn't follow the rules of the road. I had the right of way, but he still pulled out in front of me. I had to slam on the brakes to miss him. Then he flips me off like I'm the one who was in the wrong. WTF?