A Chinese doctor can't find a job in a hospital in the US, so he opens a clinic and puts a sign outside that reads "GET TREATMENT FOR $20 - IF NOT CURED GET BACK $100".
An American lawyer thinks this is a great opportunity to earn $100 and goes to the clinic
Lawyer: I have lost my sense for taste
Doctor: Nurse, bring medicines from box No. 22 and put 3 drops in patient's mouth
Lawyer: Ugh, this is kerosene
Doctor: congrats, your sense of taste is restored. Give me $20
The annoyed lawyer goes back after a few days to recover his money
Lawyer: I have lost my memory. I can't remember anything.
Doctor:Nurse, bring medicine from box No. 22 and puts 3 drop in his mouth
Lawyer:{annoyed} This is koresene. You gave me this last time for restoring my taste.
Doctor:congrats. You got back your memory. Give me $20
The fuming lawyer pays him, and then comes back a week later determined to get back $100.
Lawyer: my eyesight has become very weak. I can't see at all
Doctor: well I don't have any medicine for that, so take this $100
Lawyer :{staring at the note} but this is $20 not $100.
Doctor:;congrats, your eyesight is restored. Give me $20