A "Do it yourself" catalog firm received the following letter from one of its customers: "I built a birdhouse according to your stupid plans, and not only is it much too big, it keeps blowing out of the tree. Signed, Unhappy.
The firm replied: "Dear Unhappy, We’re sorry about the mix-up. We accidentally sent you a sailboat blueprint. But if you think you are unhappy, you should read the letter from the guy who came in last in the yacht club regatta."
Source Unknown.