I had a kid on one of my YouTube videos trying to convince everyone he was some kind of legendary rally driver. The problem was he kept saying things about rally that anyone who has ever competed, or even spectated, would know was patently false. Eventually I made mention of these flaws. He disappeared for a while, then came back with a photo of a couple of his old racing helmets to prove he was telling the truth:

Well now, don’t I feel foolish.