Here in the Washington DC metro area...we have all that have mentioned previously....and a lack of knowledge on how to merge onto or exit freeways correctly. Then there is the 'get the hell out of my way, I'm more important and have places to go' mentality that makes it more dangerous for everyone on the road.
You've gotta make some allowances for the high number of left hand exit/entrance ramps...
OK... no you don't. The fact is, having done comparisons with colleagues around the world, there are dumb, stupid, careless, insane drivers everywhere. In fact, traffic anywhere in the US doesn't hold a candle to some parts of South America or Europe...
The one thing that does really screw up driving around DC is that there's a huge number of tourists, and of transients (people living here for only a few years) who never really learn their way around. I can't tell you how many people are hopelessly lost if they have to deviate from their routine route...
But that's drifting off the thread...
More driver nuttiness that I've seen... A young woman who didn't understand why I didn't share her interest in dental hygiene, as she flossed her teeth driving down the road. Another woman who didn't understand why I stopped her for the expired inspection, driving while she was eating a bowl of soup, without a seatbelt on... The guy I saw yesterday who decided he had to make a right turn at a traffic light. OK, right on red is legal -- except that it was posted "NO RIGHT ON RED." And he was in the center lane. I don't even want to try to count the folks I've seen reading books, newspapers, working on computers, and more...
The deaf couple arguing in sign language as they drove down the road was interesting...
I gotta laugh at the morons who absolutely must get that spot in front of me in rush hour traffic (which, in this area, turns a 4 lane freeway into a parking lot)... to sit there. Even better is when you pull into a store or something right behind the moron who was fighting and weaving through traffic, driving like a nut... Yep, they saved less than 2 minutes!