Beware of those engineers

An engineer who has been unemployed for a long time decides to open an urgent care clinic. He puts a sign outside the clinic: "A cure for your ailment guaranteed for $500; we'll pay you $1,000 if we fail." A Doctor thinks this is a good opportunity to earn $1,000 and goes to his clinic. Doctor: "I have completely lost my sense of taste." Engineer: "Nurse, please bring the medicine from box 22 and put 3 drops in the patient's mouth." Doctor: "This is Gasoline!" Engineer: "Congratulations! You've got your taste back. That will be $500." The Doctor gets annoyed and goes back after a couple of days later to recover his money. Doctor: "I have lost my memory, I cannot remember anything." Engineer: "Nurse, please bring the medicine from box 22 and put 3 drops in the patient's mouth." Doctor: "But that is Gasoline!" Engineer: "Congratulations! You've got your memory back. That will be $500." The Doctor leaves angrily and comes back after several days, more determined than ever to make his money back. Doctor: "My eyesight has become weak." Engineer: "Well, I don't have any medicine for this. Here's your $1,000," passing the doctor a $10 bill. Doctor: "But this is a $10 bill ..." Engineer: "Congratulations! You've got your vision restored! That will be $500."