A man went to the doctor's office to get a double dose of Viagra.
The doctor told him that he couldn't prescribe him a double dose. "Why not?" asked the man.
"Because it's not safe," replied the doctor.
"But I need it really bad," said the man.
"Well, why do you need it so badly?" asked the doctor.
The man said, "My girlfriend is coming into town on Friday; my ex-wife will be here on Saturday; and my wife is coming home on Sunday. Can't you see? I must have a double dose."
The doctor finally relented saying, "Okay, I'll give it to you, but you have to come in on Monday morning so that I can check you to see if there were any side effects."
On Monday, the man dragged himself in, his right arm in a sling.
The doctor asked, "What happened to you?"
The man said, "No one showed up!"