Robin and I really enjoyed living in Mexico City. The only factor that made it easier to leave when the time came was the traffic. Even back then it was a constant nightmare. We liked to stay in town during Semana Santa because that was one week where you could drive around in style, speed, and safety. Shortly after we left, the City abolished the requirement of having to take any sort of driving test to get a license!
The LA Times has an article on driving schools in the D.F, that captures the flavor:
Mexico City, a seemingly infinite maze of daredevils and incompetents, of axle-bending potholes and curb-hugging taco stands, of signless seven-way intersections and baffling multidirectional traffic circles, of tamale vendors on tricycles and cops hungry for bribe money.