The power of acting 'as if'

I've read a lot about this acting 'as if' technique. Like acting slim before you are slim, acting confident even when you don't feel it. Supposedly the more you act, the quicker you'll get where you want to be. It means stepping outside your comfort zone.

I figured I was doing quite well, looking in the mirror and telling myself I didn't mind what I saw. But then I saw these Avatar fans and realised my idea of stretching my comfort zone is, well, a tad modest to say the least...