Marina Diamandis opens Froot with this emotional ballad that touches on loneliness and happiness, two of the principle lyrical themes of the album. The song lets the listener know that she arrived at her current happy place by living a more outgoing life. Marina told Spin: "'Happy' is very visceral. It's kind of a painfully, almost embarrassingly true song."
She added: "Actually the first version, like my demo, I did change a few lyrics because I went a tiny bit too full-on."
It took Diamandis a long time to write this song. She explained to American Songwriter magazine this was, "because I didn't really know what to say in the chorus and it took about four months to actually finish it."