Two turtles go camping and pack a cooler with sandwiches and beer. After three days of walking, they arrive at a great spot but realize they've forgotten a bottle opener. The first turtle turns to the second and says, "You've gotta go back and get the opener or else we have no beer."
"No way," says the second. "By the time I get back, you will have eaten all the food."
"I promise I won't," says the turtle. "Just hurry!"
Nine full days pass and there's still no sign of the second turtle. Exasperated and starving, the first turtle digs into the sandwiches.

Suddenly, the second turtle pops out from behind a rock and yells, "I knew it! I'm not f**king going!"