"The measure of a man's real character is what
he would do if he knew he would never be found out."
What I say it, "You identify yourself by what you do when no one is watching. The supervised athlete may be the hardest worker, the most selfless and responsible competitor. But how he practices when no one sees him, how he interacts with teammates when the coach is not within listening distance -- that's when he defines himself.
Theodore Roosevelt extended the definition to self-awareness and independent self-evaluation, saying, "I don't care very much about what I think of what I do. That is character!"