We always hear we should act naturally. "Just be yourself" is what you probably have heard from your mother many times. If you are a guy and ask for advice on how to get the girl you want to one of your (girl) friends, they will say the same thing: "Oh, just show yourself the way you are". I call bullshit. This is the biggest mistake you can make.
The fact is, you didn't decide who you are. During the part of your life that had the biggest influence on your character and your habits you were barely conscious (your childhood, not the times you were drunk). Why should you accept how the environment molded you into who you are? What is so worthwhile about all the imperfections in your character? What kind of self defeating loser attitude is that? If want feel proud about anything in life, shouldn't you start by yourself?
Transform into who you want to be. Behave as you want to behave. Listen to all, but subordinate to nobody as they tell you how you should be.
Push your limits. Push your comfort zone. Burn your fears. Behave as the individual you want to be, and you will eventually become that individual. That is the only worthy attitude.
We are what we repeatedly do. Excellence, then, is not an act, but a habit.