--The Doctor
Everyone makes mistakes. It's simply a fact. To make a mistake only shows that you are human. But we shouldn't make the same mistake again and again, because that would be plain stupidity.
Stupidity is lacking intelligence, and repeating the same mistake over and over is unintelligence. It's understandable to make mistakes, maybe even make it a couple more times, but never make the same mistake repeatedly; it's a waste of time and plain stupid.
