Self and the "Self" We Present to the World

"Be Yourself"
I find that incredibly difficult. If I want to impress someone, I certainly wont be myself, I'll just be all the 'good' things in me around them. Of course when i'm with someone i'm comfortable with I would probably be a lot more me and a lot less what I would want them to think I am. But I dont think I ever give anyone the whole picture. In fact, I dont really know the whole myself. I feel quite a lot of us barely scratch the surface of self awareness.
I wonder if I will ever know myself, and have the courage to let others see that 'self'. I feel much too self concious most of the time to show the world anything but what I'd like to be. If I ever find out who I really am, I wonder if i'll like him.