"$10 of technology" joke

Bob complained to his friends "My elbow really hurts. I guess I
should see a doctor."
His friend offered, "Don't do that!!! There's a computer at the
rugstore that can diagnose anything, quicker and cheaper than a
doctor. Simply put in a sample of your urine and the computer will
diagnose your problem and tell you what you can do about it. It
only costs $10. 00."
Bob figured he had nothing to lose, so he filled a jar with a
urine sample and went to the drug store. Finding the computer,
he poured in the sample and deposited the $10. 00. The computer
started making some noises and the various lights started
flashing. After a brief pause out popped a small slip of paper
on which was printed:

You have tennis elbow. Soak your arm in warm water.
Avoid heavy labor. It will be better in two weeks.

Late that evening while thinking how amazing this new technology
as and how it would change medical science forever, he began to
wonder if this machine could be fooled. He decided to give it a
try. He mixed together some tap water, a stool sample from his
dog and urine samples from his wife and daughter. To top it off,
he masturbated into the concoction.

He went back to the drug store, located the machine, poured in
the sample and deposited the $10. 00. The machine again made the
usual noise and printed out the following analysis:

Your tap water is too hard. Get a water softener.
Your dog has worms. Give him vitamins.
Your daughter's on drugs; put her in rehab.
Your wife's pregnant. It ain't yours---get a lawyer.
And if you don't stop jerking off, Your tennis elbow
will never get better.