1. people who assume in an emergency that since washer fluid is blue and refreshing looking, it will help them put out an engine fire, with the results you can imagine.
(have to own that one, though I was sleep deprived)
2. Certain people who consistently slam their auto transmission gear lever as hard as possible upwards when its time to stop, who slam it down as hard as possible when its time to go, and never actually verify what gear the lever is actually in. The same people who are capable of driving extended distances in 2 or 1, and call yelling about how slow the car is as it revs along a 5000 rpm!