I once heard a tale from a a Vulcan Nav or AEO. His aircraft was on a lone ranger to somewhere east.
He said the flight was long and uneventful, he was feeling tired and could feel his eyes getting heavy. He couldn't resist the onset of fatigue and thought to himself it would be okay if he had a few minutes kip as all the other crew were there.
He work up an hour later to find the Vulcan had drifted off course by such an alarming amount they had to divert low on fuel.
Apparently every one in the crew thought the same thing and all 5 had nodded off.