A hospital recently hired several cannibals.
"You are all part of our team now" said the Human Resources rep during the welcoming briefing. "You get all the usual benefits and you can go to the cafeteria for something to eat but please don't eat any of the other employees."
The cannibals promised they would not.
Four weeks later their boss remarked "you're all working very hard, and I'm satisfied with you. However, one of our secretaries has disappeared. Do any of you know what happened to her?"
The cannibals all shook their heads.
After the boss had left, the leader of the cannibals said to the others, "which one of you idiots ate the secretary?"
A hand raised hesitantly, to which the leader of the cannibals continued "You idiot!!! For four weeks we've been eating managers and no one noticed anything, but noooooo, you had to go and eat someone important!"