A woman walks into a pharmacy and asks the pharmacist for a lethal dose of arsenic, which she intendeds to poison her cheating husband with. Horrified, the pharmacist rejects her request.
"I could lose my licence! I could be tried for being your accomplice to murder! There's absolutely no way I wouldever give you such a thing!"
The woman reaches into her purse and produces a photo of her cheating husband in bed with the wife of the pharmacist.
He looks at the photo with shock, then replies, "Oh, well, why didn't you tell me you had a prescription in the first place?"