After coming to Japan, I've noticed that I drive differently than I used to beforehand. And I don't mean on the other side of the street!
For example, I often put my automatic car in neutral and put on the emergency brake when I'm at a red light, or I know I will be stopped for an extended period of time.
Also, I sometimes turn off my headlights at night when I'm waiting at a red light. I turn them back on when it turns green, of course!
Also, I use my hazard lights A LOT more than I ever used to! For thanking the guy behind me for letting me in the expressway, to signify that I'm backing up, to signify that I'm making an ubrupt stop on the expressway, to signify that I'm parked, but I'll be back in my car soon, etc.
That's all I can think of off the top of my head. How about you? Have your driving habits changed since coming to Japan?