I find it interesting how this topic evolved. It started out with the question, How do you cope with irresponsible drivers? to ... examples of irresponsible drivers and how wrong they are and how to defend yourself against irresponsible drivers. I don't think that is what the OP was asking about. But, ...
Lots of good answers I've see so also. I think the good responses are those who don't sweat the small stuff, those who ignore idiocrasy, those who drive defensively, those who maintain their whits about themselves, and those who know bad drivers are just a way of life and don't let them get under their skin.
I am reminded when I experience idiots on the road, who are speeding, driving reckless, being a hazard to other drivers, obnoxious, and just plain irresponsible and self centered, that I served in the armed forces to safeguard THEIR freedom so they act that way.