Today I came across to this way of thinking twice. Earlier I read a beautiful post by @jaynie where it was described, what we think, we eventually become, and now same concept but different wording.
We, humans, are menifestation of our thoughts and everybody's personality is basically menifestation of what he thinks about himself.
I wanna add one thing here, those who want to become something but cannot change their thoughts and ultimate personality, this quote suits them; "Fake it until you make it", or more better to say, "Fake it until you become it".