In most situations, being able to "fake it til you make it" is a major asset. Whether at work or a social situation, an injection of confidence and face can go a long way, especially since most other people don't know what they're doing.
However, there are times when the "fake it til you make it" ethos can fall short, and the smile-and-nod confidence can get you in way over your head. If you've ever had your mask of fake confidence knocked off in a moment of reckoning, then you know exactly how bad it can get.
At Nelson Mandela’s funeral, people took note of the sign language interpreter that seemed to just be making random hand gestures instead of actual sign language. Turns out he had made quite a few appearances previously and nobody had caught on that he knew literally no sign language. To me, this dude is just the poster child for "fake it till you make it’"