People in DC drive terribly. People in Boston drive terribly too. I imagine drivers in most major cities are terrible.
I think it's the congestion. Traffic moves slowly enough that drivers can get away with doing things that would be deadly at higher speeds, and streets are crowded enough that there is little chance of them being pulled over for it.
There are two offenses that particularly irritate me. Number one: honking.
City drivers honk persistently, and I do not understand it. Mostly, they honk when traffic is moving more slowly than they would like, which is often. Perhaps they are under the impression that they are contributing to improving traffic flow by leaning on the horn, but believe me when I say that they are wrong. Most likely, it is the only outlet for their frustration with the fact that it can take 20 minutes to travel 1 mile in city traffic.
For you, city driver, I have two words: public transportation. Sooner or later, increasing population density will make city driving prohibitively slow, and you will give it up. Until that time, please stop honking. You are giving me a headache.