This fellow comes into a pharmacy and asks for a vial of cyanide. The pharmacist, trying to keep a professional posture, asked what he wanted it for.
The fellow said, "I want to kill my wife."
"I'm sorry Sir," the pharmacist replied, "but you will have to understand under such circumstances I can't sell you any cyanide."
The guy reaches into his wallet and produces a photo of his wife, then shows it to the pharmacist.
The pharmacist blushes and replies, "I am sorry, sir, I didn't realize you had a prescription."