This has happened to me a lot and it's always embarrassing. I have one of those faces that doesn't change much. Obviously, I'm older, but if you see pictures of me from kindergarten all the way through to now, it's pretty easy to tell it's the same person.

Some people change a lot. And I can never bring myself to tell the person I have no clue who they are after they go on about how I haven't changed, etc. I don't want to hurt their feelings. Some of them still remain a mystery to this day.