“Best Friend” is about unrequited love. The protagonist is in love with a girl and even though it should be simple for them to be happy together she just doesn’t love him back. But still they get along so well that she might ask him to stay friends.

The song is an exploration of the intricacies of love, the feeling of loss, and the warmth of nostalgia with the knowledge that the end of a romance isn’t the end of knowing someone who you love.