"Fake it 'till you make it" has so fundamentally changed how I function.
It's not so much that you're bullshitting and it's turning to gold - it's that you pretend to be comfortable in a situation where you are not, and then as you get used to it you become comfortable, and then you "make it."
Basically, you're not going to suddenly become great as a CEO, but if you don't at least give off SOME confidence, your employees, partners, board, competitors, customers won't have any faith.