when someone is standing here, I end the conversation w/ coworker (about inventory--I don't discuss it to openly because I don't need people to know that there are 10 balances [street value for balances is HUGE around here.] in my office, etc) and ask if I can help him.
"oh, I was just listening to what you guys were talking about"
WTF?
(actually, I think he used the word 'evesdropping'.)
He isn't even the creepy guy...just an idiot.
I just stared blankly at him until he went away.