I once entered a bar and recognised a fellow and he recognised me (or so we thought). We greeted each other by first name: “It’s so-and-so isn’t it?” “Yes, and you’re so-and-so, aren’t you?” “Yes, that’s right!” We started to converse but after a couple of minutes it become painfully obvious that we had both made a mistake . . . we had both mistaken the other for someone else . . . and yet we both got the other’s first names correct!
Now that’s an unusual thing to happen!