My office isn't very high (I'm on floor 9 of a 10 story building), but given that it's high enough, I get very used to pretty much nothing changing outside my window. Sure, clouds, etc., occasional birds, but never anything very big.
All of a sudden, this guy was right outside my window, watching me eat lunch. Well, actually, he probably couldn't have cared less. I almost screamed though.
That goes on the short list of jobs you couldn't pay me enough to do.