Why is that guy winking at me? Do I know him or what? It turns out that this person has an extreme form of some kind of tic, the muscles in his face jerking all over the place, that usual winking reflex triggered by some unknown neurological cause. Spastic and uncontrollable. Of course, the instant reaction is to assume that he knows what he is doing and therefore that he recognizes you for some reason. But that is not the case, pass him by and continue life as usual.