That moment when you’re conversing with a friend over lunch in a restaurant close to your office and you recognize the man who has just walked in as one of the many semi-attractive frat guys who used to mill around the cafeteria in college, and he recognizes you too (you can tell because he looks at you a little too long), but neither of you says anything because neither of you ever knew each other’s name.  And if you ever did, you’ve forgotten it by now.