One of those FB "memories" from 2009:
"minor celebri-fail: I just autographed a starbuck's cup for a young woman who turned out to be disappointed I wasn't actually Dave Matthews."
This really did happen, a mutual misunderstanding in which I genuinely thought I was being asked to sign as Dr Frank, while she was under the impression that she was getting Dave Matthews. I watched her delight turn to confusion, then to desolation. I've never seen a more disappointed face.