Theres a PA system at the top of Dr. Dooms Freefall (drop tower) at Islands of Adventure and as we reached the top the op said in an evil voice:
"OK, we're going to countdown until you plunge to your death. 13, 12, 11, 10, 9" *at this point the ride drops*
What I've never heard but would never want to hear waiting for a flat launch coaster:
"I wonder what would happen if we turned the power to maximum... has anybody here ever gone 200 MPH outside of an airplane or bullet train?"
Or on a spinning ride:
"If at any time you feel nauseous, place one hand over your mouth and another hand in the air. This way you will puke more on yourself than anybody else and other riders can prepare for when you spew, since theres no way in hell I'm stopping this ride."