Like this amusing little anecdote, which will probably be quoted incorrectly (it was a while ago), but was damn funny all the same. It has been attributed to my fellow gamer Nick.
D&D game, and we're heading into (what else?) a dungeon/maze thing. We're walking in and our DM describes the terrain, which is mostly stone/dirt tunnels, lined with burning torches.
Nick: Why is that?
DM: Why is what?
Nick: Why is it that whenever a party walks into a dungeon, the torches are still burning perfectly? I mean, shouldn't they have burnt down by now, or is there, like, some guy wandering around fixing torches?
DM: *to get on with it* It's, um, magic. Yes.
Nick: Oh. ... [intones] There was once an exalted sorcerer who cast a spell in all dungeons to have torches burn eternally! His name has been forgotten, but his legacy lives on!!