To tell a friendly white lie that makes the story better also known as a exagalie. To add something that may or not have happened to enhance a story or tale.
When I was 12 I threw up on the airplane one time. My mom now tells everyone that when I fly that I throw up every time. I had 8 beers on my 30th birthday but when I talk about that night now I tell everyone that I had 16 beers. So these are known as exagalies.