It seems like such an easy thing to do, to recall a person you saw weeks, days, or even hours earlier. But it's not...
Student: "That reminds me of a presentation I sat through during freshman orientation."
Me: "Right, I was one of those presenters."
Student: "No, there was a Black professor and a White professor, but the White guy was someone else."
Me: "Actually, that was me. I conduct diversity workshops, including that one at freshman orientation."
Student: "No, the White professor wasn't you; it was another guy."