Fred's wife has been feeling strange for weeks, so she goes to the doctor and undergoes a series of tests. A few weeks later, the test results are in, and the doctor calls Fred into his office, alone. "What is it, Doctor?" Fred says. "Is she going to be okay?"
"I'm sorry, Fred," the doctor says. "I wanted to break this to you first. Unfortunately, we've had a chart mix-up with another patient, but the news isn't good either way."
"What's wrong?" Fred asks.
"Well, she either has Alzheimer's or AIDS."
"Oh god, what should I do?" Fred cries.
"Well," the doctor says. "I suggest you drive her three miles out of town and drop her off. If she finds her way back home, don't fuck her."