On a sky diving trip the instructor tells the student, “Jump out, count to three, pull the cord, and the chute will open. If something goes wrong, just pull the emergency cord and the chute will open. There will be a truck below to pick you up. Good luck, have fun!”
The student jumps, counts: “one, two, three...,” and pulls. Nothing happens. He grabs the emergency cord and pulls. Again, nothing happens.
Disgusted he says to himself, “I bet there's no truck down there either!”