Songfacts®:

• Los Angeles singer-producer Gnash paired up with Bay Area singer-songwriter Olivia O'Brien to create this song. O'Brien originally wrote the track and already had a working relationship with Gnash having covered his tune "Disposable." They met up in LA and Gnash reworked the beat and added a verse. Released as a single, it became the first chart-topper in Australia for both artists.
• The song is about the aftermath of a breakup when both parties are still missing each other. While O'Brien is still in the same emotional place as when they broke up, Gnash has partly been able to move on. He sings:
  
  I know that I control my thoughts and I should stop reminiscing
  But I learned from my dad that it's good to have feelings
  When love and trust are gone
  I guess this is moving on
  
  Gnash explained in a Genius.com attribution: "I never really felt what moving on felt like, even after the first time we broke up, because the door never really closed. This time because I'm deciding to I'm actually feeling it and it sucks. This is actually also a reference to the line 'I guess this is growing up' in Dammit by Blink-182."
• Olivia O'Brien told ABC Radio that she originally wrote the song as she was "sad about a boy." She added, "I have hundreds of songs from my freshman year... where I would just write about all the boys I liked... and they're all so bad! This one just turned out to be good!"
• Olivia O'Brien released her solo version of the song titled "Hate U Love U" on March 20, 2016. Her rendition peaked at #99 in the US.