One day, in line at the company cafeteria, Al says to Mitchell behind him, "My elbow hurts like hell. I guess I'd better see a doctor."

"Listen, you don't have to spend that kind of money," Mitchell replies. "There's a diagnostic computer down at Wal-Mart. Just give it a urine sample and the computer will tell you what's wrong and what to do about it. It takes ten seconds and costs ten dollars . . . A lot cheaper than a doctor."

So, Al deposits a urine sample in a small jar and takes it to Wal-Mart. He deposits ten dollars, and the computer lights up and asks for the urine sample He pours the sample into the slot and waits. Ten seconds later, the computer ejects a printout:

"You have tennis elbow. Soak your arm in warm water and avoid heavy lifting or strenuous activity. It will improve in two weeks. Thank you for shopping [at] Wal-Mart."

That evening, while thinking how amazing this new technology was, Al began wondering if the computer could be fooled. He mixed some tap water, a stool sample from his dog, urine samples from his wife and daughter, and a sperm sample for good measure. Al hurries back to Wal-Mart, eager to check the results. He deposits ten dollars, pours in his concoction, and awaits the results.

The computer prints the following:

1. Your tap water is too hard. Get a water softener. (Aisle 9)
2. Your dog has ringworm. Bathe him with anti-fungal shampoo. (Aisle 7)
3. Your daughter has a cocaine habit. Get her into rehab.
4. Your wife is pregnant. Twins. They aren't yours. Get a lawyer.
5. If you don't stop playing with yourself, your elbow will never get better!