Songfacts®:

• This song finds Chainsmokers going back to their dance roots as they aim for an upbeat summer vibe after several darker releases. It also finds them linking up again with frequent collaborator Emily Warren, who supplies the soulful croon and also co-penned the track. (She co-wrote the Chainsmokers' hit "Don't Let Me Down." and sung on another of their successful singles "Paris.")
  
  Warren's writing resume also includes Sean Paul's "No Lie" and Dua Lipa's "New Rules."
• Lyrically, this song is about the consequences of making bad decisions in relationships. However, Chainsmokers' Drew Taggart explained to Billboard it's also about accepting such "side effects" because when Emily Warren sings of making the drunken decision to embark on a fling, she finds "beauty in those small moments."
• The video, directed by Matthew Dillon Cohen, stars actress Camila Mendes of The CW's teen drama Riverdale. She portrays a fed-up Miami hotel employee named Riley who's less than enthused to learn she'll be working all weekend. Riley takes her frustration out by dancing her way through the shift. Did you spot The Chainsmokers duo during the segment when we glimpse inside each hotel room?
• Unlike Emily Warren's other collaborations with The Chainsmokers, the songwriter penned "Side Effects" in a separate writing camp before the song found its way to the dance duo. Warren recalled to Billboard that she woke up to an accumulation of missed calls and text messages from The Chainsmokers, urging her to let them record the tune and assuring her they would keep her voice on it.
  
  "So that was the quickest ever turnaround of writing a song and having it come out, and it's been awesome being featured on it," she added.