There is a saying that has become so commonplace that some people take it at face value. For some reason it really drives me nuts. The saying is: Insanity: doing the same thing over and over and expecting different results. The saying has been attributed to Albert Einstein, Mark Twain and others and is misquoted time after time.
Salon.com has called it "the most overused cliche' of all time" and it's also been called "the dumbest thing ever said by a smart person".