A man goes to the pet store...

And walks up to the shopkeep.

"I'd like to buy a dog please," the man said.

"Certainly sir, I think I have one you might like," replied the shopkeep.

The shopkeep then leads the man through to a room separate from the rest of the shop, that's completely empty except for a dog sitting on a dog's bed.

"Hmm, nice looking dog there," the man says.

"Thanks mate, I always appreciate a compliment," says the dog.

The man steps back in amazement.

"A talking dog, that's incredible! What are you doing here?"

"Well," the dog says, "I'm trying to keep a low profile. You see, I've been around a long time, and I've seen some things. I used to work for the CIA; best spy they ever had. As soon as they knew I could talk they sent me all over the world listening in to top secret conversations so I could report back to them and save the world. It's because of me the Berlin Wall's down."

"That's amazing!" Says the man. "But how did you end up here?"

"Ever since I was fired from the CIA for being too heroic, I've just been wandering around, telling stories to those who'd listen. I even told an old friend of mine an idea I had for a film once. A few years later that became Star Wars. But now, after a life of pure excitement and extreme living, I just want to settle down peacefully, so here I am."

The man is completely awestruck by all of this. "I'll be back in just a minute."

The man then walks back to the shopkeep.

"I'd like to buy that dog, please."

"Certainly, sir. That'll be ten dollars," the shopkeep says.

"Ten dollars?! Why? He's a talking dog!"

"Yeah, I know," replied the shopkeep, "but he's such a liar!"