everyday revalations, some surprising, but not

You ever know some one for a long enough period of time, only to realize that they're not really who they have always claimed to be and acted like they were? Figuring this out, simply by paying attention to the details in what they say, and then seeing them do something that completely refutes and reverses everything they just said? Given a long enough time, every question's answer is one that eventually, when the real answer finally comes out, will be contradicted by said truth... It's something that I guess is done from time to time by most, but there are those people that take this way of living to an entirely different level, suggesting that they are in such a delusional state that makes you wonder what they really call reality, and just how far removed from ours they are? How do they function in an everyday world like ours? More than that, how do we interact with them?