I once interviewed a guy who went on and on (and on and on) about how he had written a program with an IF statement and a loop. I was in the room with another manager who thought she might need him if I didn't and she had her head tilted down so her hair could cover the fact that she was crying because she was laughing so hard. He didn't even notice.
Then, after 8.5 years with that company, I went back to the MUCH higher paying consulting and ended up at the company that same guy was trying to "upgrade" from. The put me in a 4' by 4' cube with short walls two cubes away from that guy who was completely paranoid that I would tell everyone he was looking for a new job. I didn't, but I did have to admire his ability to fall asleep sitting straight up in his chair, looking at the monitor with his hands on the keyboard. No idea how he as able to do that!