Sleeping in a Dungeon
The A,D&D core book stated that wizards could only memorize spells in the morning, and also only after eight hours of complete rest. The bigger dungeons occasionally demanded that people sleep in the dungeon in some safe corner.
These two aspects never sat well with me. I kept picturing the party's fighter lecturing some poor mage:
Rest well! Don't worry about the monsters, or worry about nightmares. We're gonna need your spells in the morning, so have sweet dreams, or we're going to be down a party member, and we need everyone we can get. We're off soon, so don't spend too long getting to sleep. If you don't fall sleep now, no spells, and you'll end up being eaten by some monster without that wizard-shield, and likely the rest of us will too without your fireball spell.
So don't stay up all night worrying like last time, or we could all die.
Okay, night, night - sleep tight!