I did this when i was young...in a hospitol...and when i turned around i had this stupid smile on my face and just said "Welcome back..so glad to see you again" i rode that elevator for a good 30mins before i was finaly joined by someone who dident try to talk to me... makes me think wtf i was doing when i was younger..
well, I used to stare at people when they'd ask me a question because I was thinking about the answer. also, I once took over the daycare because the baby sitter was a moron.