Share the pain
A man took his pregnant wife to the hospital to give birth, and the doctor told them that he had developed an experimental machine and asked if they'd like to try it out. He explained carefully that the machine could take some of the pain of childbirth from the mother and give it to the father.
Both the husband and the wife thought this was a wonderful idea, and decided to give it a try. The doctor set the knob on the machine to ten percent for starters, explaining to the man that even ten percent was probably more pain than he had ever experienced. But the man was surprised at how little pain he felt and asked the doctor to go ahead and turn it up a notch.
The doctor twisted the knob up to twenty percent, and checked the husband's blood pressure, which was fine. Amazed, the doctor turned the knob again and increased the pain threshold to fifty percent.
Still feeling nothing, the husband encouraged the doctor to give him ALL the pain. Again, dumbfounded, the doctor increased the load to one hundred percent. After his wife had given birth, the man stood up, stretched a little, and helped his wife into the car, both of them feeling fine.
When they got home, they found the mailman dead on the doorstep.