"Talking Dog for Sale"

A man is driving down the highway and sees a sign off the road that reads:

"Talking Dog for Sale. Next Exit."

He has some time to kill and is curious, so he pulls off the exit and follows the signs. The signs lead him to an old farmhouse where an old man is sitting on the porch in a rocking chair. The main gets out of his car and says, "Excuse me! I'm here about a talking dog" The man nods his head and says he's around back in the doghouse. The man walks to the back and sees a dog laying down. The man hesitantly asks, "Are you the talking dog...?" The dog quickly hops up and explains, "Why yes, sir! I am! I've been talking my whole life. When I was just a pup I was recruited by the FBI and served for many years as a covert American spy. I helped bring down many Russian officials and have received numerous medals for my service. I've also met every sitting President in my lifetime and am also an accomplished translator for the UN."
The man is stunned. He goes to the porch where the old man is still rocking. The man excitedly asks, "Mister, that is the most incredible dog I have ever seen. Why on earth would you want to sell him?!"

The old man replies, "Because he's a liar he didn't do any of that shit!"