Songfacts®:

• Over atmospheric synths and strings, Phoebe Bridgers sings of finding a new lease of life through a connection with another person. She used to just observe the world around her while sitting on the sidelines, but her circumstances have changed. Because Bridgers has found security and comfort in her lover, she is now more active and engaged.
• Bridgers wrote "Sidelines" for the TV series Conversations with Friends, a Hulu and BBC 3 adaptation of Sally Rooney's 2017 novel of the same name. The storyline details the relationships between a married couple and two college students who are best friends.
• Bridgers wrote the song with her drummer and frequent collaborator Marshall Vore, and with Runy Henley. Bridgers and Vore also co-produced the song with her Punisher producers Tony Berg and Ethan Gruska.
• The music video features footage of Bridgers recording the song in the studio alongside clips from the 12 Conversations With Friends episodes.
• The song's self-affirmative tone is more optimistic than Bridgers' previous material. "I'm striving to do more stuff like that," the singer-songwriter told Variety of her shift in focus. "I think it's more challenging to sound smart and write well about happiness than it is about sadness. In the interest of not seeming trite, I lean toward darker subject matter, just out of comfort. And I think a challenge to myself, now, is being articulate about things that are good."
• Bridgers read Conversations With Friends in 2019 and immediately felt a particular affinity for the book's narrator, Frances Flynn. "I feel like I'm more similar to Frances than any character in pop culture, ever," she said. "Frances is so, so confident in her own art – she knows she's great, and she thinks she's the smartest person in the room – but she's also so deeply, deeply self-conscious. And that balance in a person was super jarring to read for the first time."