As much as I dislike the expression (not because of the concept... the phrase itself is rather unpleasant to hear, what with the hard "k" and long "a" sounds)... it does have some merit. Did you know that, if you force yourself to smile, the muscles in your face will send signals to your brain, and the brain will perceive these signals as happiness... as a result you will actually become happy...

I also heard a story of a professional con-artist who, using his charm, wits, and completely fake credentials, weaselled his way into an upper-managerial position. He "faked it" for so long that he actually learned a lot about the business and was able to do a fairly decent job... That is, he made it...