A man writing at the post office desk was approached by an older fellow with a post card in his hand.
The old man said, “Sir, I’m sorry to bother you but could you address this post card for me? My arthritis is acting up today and I can’t even hold a pen.”

“Certainly sir,” said the younger man, “I’d be glad to.”
He wrote out the address and also agreed to write a short message and sign the card for the man. Finally, the younger man asked, “Now, is there anything else I can do for you?”

The old fellow thought about it for a moment and said, “Yes, at the end could you just add, ‘P.S.: Please excuse the sloppy hand-writing.’”