The Talking Dog

One day, a man was going through personal ads and came across an ad for a supposed talking dog. When he sees this, he's immediately interested and decides he would check it out for fun. He contacts the person who posted the ad and is on his way in no time.

So he arrives to the owners house, and asks right away where the dog is, the owner tells him "The talking dog is in the back yard tied to the fence, go right ahead." The man enters the back yard and approaches the dog with caution. "Hello" said the man, feeling somewhat naive for talking to a dog. Sure enough, the dog says "Hello" back. The man is startled and in disbelief at the same time.
"Wow, this is insane! A talking dog!?" exclaimed the man, still having a hard time believing what he was seeing."This is a huge deal!"
"Yeah, it is something special" said the dog with a tone of pride.
"Due to my unique ability to talk, my life has played a significant role in several events in history." The talking dog then went on to explain how he was pivotal in the success of the Allies in WW2. He talked about how without him, MLK Jr. wouldn't have been able to deliver his speech in August of 1963. The dog touched base on his work as an informant for the Watergate scandal. On top of all of this, he was a survivor of terminal cancer.
The man was clearly in more disbelief than before "I'm going to have to stop you right there, this is all so much information to take in. I want to buy you without a doubt." The man rushes back inside the house. "I will take the dog!" He says while full of excitement. "But.. I have to ask you, why on Earth would you want to sell such an extraordinary dog?" The owner looks at the man and says "Because he's a fucking liar."