Let's not forget that drivers think they're better drivers than everyone else on the road.
Right. They think they are better not in the sense that they can equitably share the road with other motorists, but because they believe they are have l33t skills at handling their car and have cat-like reflexes that allow them to tailgate and whip around slower motorists with precision.
What they don't realize is that these qualities are exactly what a good driver isn't. Good drivers are defensive drivers who have a larger awareness of the roadway than just simply their selfish needs to get to point B as quickly a possible; good drivers tend to "share the road" with other motorists. Collisions are caused by conflicts in the roadway. Aggressive drivers who think they are good drivers cause more conflicts than defensive drivers. When you get two aggressive drivers causing a conflict at the same time, you have an accident. (I'm not saying that this is how all accidents happen, just preventable ones)
I think this also stems from people passing judgement on other motorists when they do something unexpected to them. They think they are a better driver because they are appalled at all these other drivers pulling out in front of them, driving too slowly in front of them, taking their time making a right turn, etc. They conveniently forget all the other times they pulled something stupid in front of someone else because they were either too busy focusing on getting to point B, or think themselves above other motorists. The automobile is a powerful psychological device that gives people their only opportunity for power trips, so to speak, since they feel powerless in the stresses of their life off the road.