"What Hurts the Most" is a song performed by the country music trio Rascal Flatts. It was released as a single from their album "Me and My Gang" in 2006 and became their fifth number-one single on the US Billboard Hot Country Songs chart. The song was originally written by Jeffrey Steele and Steve Robson and recorded by Mark Wills in 2003. The lyrics describe the pain of losing someone and the regret of not telling them how much they were loved. The song has been covered by several artists and has been featured in various TV shows and movies.