"Best Days of Your Life" is a song by American country music artist Kellie Pickler. It was written by Pickler and American singer-songwriter Taylor Swift who also provides background vocals on the song. It was released on December 1, 2008, as the second single from Kellie Pickler's second album Kellie Pickler. The song is about a narrator explaining how her former boyfriend cheated on her and moved on to a new girlfriend to start a family with, wishing them well on their new life but says that the new girl won't top what they previously once had before.