A dentist completed a clean and neat job on a patient and the patient was pretty happy with him. So, when the doctor asked him for a favour he was all willing to help, but was confused when the doctor asked him to give out a few loud and painful screams. The patient asked, "But why doctor? It wasn't all that bad this time."
The doctor replied, "There are so many people in the waiting room right now, and I don't want to miss the four o'clock ball game."