I'm going to go out on a limb and say that the mark of a great teacher is when a student remembers what you taught 22 years later, and applies it every day. In my case, this was my driving instructor. Mr. Karr. Need I say more?
Today I found it necessary to apply the "never trust anyone who is waving you through" rule. My route to work includes a left turn off of a five lane road (including a left turn lane) which can occasionally be dicey. Today I got to the turn just as on the on coming traffic got very heavy. A couple of people tried to be nice and stopped to let me through. The problem was that the lane on their right wasn't stopping for anything. The second guy actually blinked his brights at me to indicate that it was fine for me to turn, meanwhile cars are whizzing by him on his right. He threw me a pretty withering look as he passed. Whatever. I might survive someone smashing my passenger side at 40 MPH, but my car wouldn't, and I like my car.
Some other Mr. Karr rules:
+ Don't go where you don't fit.
+ Use your turn signal, and use it correctly: don't turn it on halfway through the turn or a block and a half away from your turn.
+ Don't trust someone else's turn signal. They may not know the above rule.
+ Don't run red lights.
+ Pay attention to what is going on around you (my sister remembers him asking what color the car behind her was, while covering the rearview mirror).
+ Pay attention to the speed limit.
+ Don't tailgate.
If more people followed Mr. Karr's rules, driving would be a much more pleasant experience. This is not to imply that I am a great driver, my attention span is really bad and I do make some boneheaded moves, but I try to follow Mr. Karr's rules.