It was time for the annual blood drive. He told his girlfriend, "I'm going to give blood tomorrow." She said, "Don't do that. You could get a disease." He asked, "I could get a disease? How could I get a disease?" She said, "You never know. What if a nurse trips and stabs you with a dirty needle?" He said that was ridiculous. Nurses don't trip. Nurses don't stab blood donors with dirty needles. He went to the blood drive the next day. He watched the nurses carefully. None of them tripped. None of them stabbed a blood donor with a dirty needle. He gave blood. He told his girlfriend that no one had tripped and stabbed him. She said he was lucky this time.