A doctor is struggling to find work, so he opens his own clinic and puts a sign outside that reads ‘GET TREATMENT FOR $20 – IF NOT CURED GET BACK $100’. A lawyer walks past and thinks this is a great opportunity to earn $100.

Lawyer: I’ve lost my sense of taste.

Doctor: Nurse, bring medicine from box No. 22.

The doctor then puts three drops in the patient’s mouth.

Lawyer: Ugh! This is kerosene.

Doctor: Congratulations, your sense of taste has been restored. That’ll be $20.

The annoyed lawyer goes back after a few days to recover his money.

Lawyer: I have lost my memory. I cannot remember anything.

Doctor: Nurse, bring medicine from box No. 22.

The doctor then puts three drops in the lawyer’s mouth.

Lawyer (annoyed): That is kerosene. You gave that to me last time for restoring my taste.

Doctor: Congratulations. You’ve got your memory back. That’ll be $20.

The fuming lawyer pays him, and then comes back a week later, determined to extract $100 from the doctor.

Lawyer: My eyesight has become very weak. I can’t see at all.

Doctor: Well, I don’t have any medicine for that, so here’s $100.

Lawyer (staring at the note): But this is $20, not $100!

Doctor: Congratulations, your eyesight has been restored. That’ll be $20.