The real test is this one: When you’re alone in a room, when you’re in a private place and nobody else can see you, what do you choose to do? Eat well, or eat poorly? Exercise, or watch television? Practice something, or do nothing? The best version of the truth appears to you and you alone, when nobody else can see. This is the test of discipline, and it’s what makes the difference in your life. It’s what regulates your own system and guides it. The individual alone comprehends it.