Danielle Bradbery wrote this song with Hannah Ellis and Josh Kerr. She told Billboard magazine the story behind the track:
"The song 'Messy,' it's about a relationship - all relationships can be like a rollercoaster, whether you're together or not. I was just not having the best day and I was trying to be professional and keep it all together. When some of the people left the studio, it was just me and the two writers and they were like, "Are you okay?" I was like, 'No, I'm really not.'
We just started talking just about life and how, again, relationships can be hard and you have these big bumps in the road you try to overcome. I just wanted to let it out and told them stories that I normally really wouldn't tell anybody, and we made a song out of it. I went in the recording booth and they turned down the lights and lit a candle -- it was all about the mood. Literally, when I say [songwriting] is like a therapy session, it is like a therapy session [Laughs]. That was one that was really a lot of deep secrets."