Mulla Nasruddin's doctor sent him a bill. It was too much. His child was ill: Nasruddin's small son was ill. He phoned to the doctor that "This is too much." The doctor said, "But I had to come nine times to see your son, so that has to be accounted for." Nasruddin said, "And don't forget that my son infected the whole village, and you have been earning a lot. In fact you should pay me something."