Tom: Hey Jack, Joe told me he flew his car into a skyscraperthe other day!
Jack: Really? I was at his house yesterday, and there wasn't even a scratch on his car.
Tom: Yeah, Joe is pretty good at telling stories. We don't even live close to a city.
A response to a possibly false statement that one gives when the party being responded to is certainly deluding themselves. Roughly, "If you keep saying that, you might actually start to believe it".
"The price of gasoline is going to go down tomorrow," quipped Sue. Joe simply responded, "You keep telling yourself that."