It was written by bassist Mark Hoppus, drummer Travis Barker, and guitarist Matt Skiba, as well as producers Andrew Watt and John Feldmann, and songwriters Ali Tamposi and Nathan Perez.

"[3] An early edit of the song, featuring guest vocals from pop singer Miley Cyrus, surfaced online in April 2020.

[4][5] Andrew Sacher of BrooklynVegan described the song as "ultra glossy pop", stating that it is better suited for Taylor Swift's Lover, which was released two weeks before "I Really Wish I Hated You".

[7] The band first teased the release of "I Really Wish I Hated You" on September 5, 2019, utilizing an automated phone number that, when texted, revealed a snippet of the tune.

[9] The band played the song live for the first time only days later on September 12 at the Xcel Energy Center in Saint Paul, Minnesota.

[13] Grant Sharples of online magazine Consequence of Sound similarly found its lyrical content "elementary", "forgettable," and repetitive.

"[16] In contrast, Billboard columnist Bobby Olivier ranked it the second-best song on the LP, an "earworm" with the "right mix" between modern production and the band's catchy past.

"[18] Pitchfork contributor Nathan Smith viewed it a transparent bid for mainstream popularity, theorizing it was inspired by the Chainsmokers,[19] with whom the band indeed collaborated with later in 2019 with the single "P.S.