Romero's Wager
The principle that being prepared for impending zombie apocalypse is the safer bet than not being prepared, as the loss if one is incorrect is minuscule in relation to the reward if one is correct.
"Dude? Why do you have a chainsaw and a sawed-off in your umbrella stand?"
"Romero's Wager, man."
"Romero's Wager, man."