When I was a sysadmin at the University of Pennsylvania, one of the grad students asked me if I knew that “gullible” was missing from the dictionary. This is the oldest trick in the book.
“Huh, really?” I said, and turned to my open terminal session. “Lemme see…”
“…How about that! It's true!”
He was very surprised, and somewhat annoyed that his trick hadn't worked.
Wouldn't you expect that