A guy walks past a pet store. There is a sign in the window that says "talking dog for sale." He goes in, walks up to the dog and says "how has your life been as a talking dog?"

The dog says; I've had a long, full life. I worked in the Alps saving avalanche victims, served in the army for four years, saving soldiers from land mines, sniffed out drug dealers in airports, and now I spend my days delivering food to the elderly.

The guy turns to the pet store owner and says "why in the world you sell a dog like this???"

The pet store owner says "because he's a damn liar. He never did any of those things."