This exploration of the emotional pain involved where lovers are being torn apart is one of many tracks on Memoirs of an Imperfect Angel with the theme of heartbreak and/or betrayal. Carey has stressed in interviews that the songs have nothing to do with her husband Nick Cannon but instead hark back to when she was younger or are inspired by stories told in movies and by friends.

This was the first song that Carey wrote for the album.

The initials in the song title stand for "Having A Typical Emotional Upset."

This song features Carey's trademark soprano, but in a different way than before. She said in publicity materials: "I sing a recurring melody in the upper register of my voice; it's not an ad-lib, but an integral part of the song's hook. That's not something I've done before, and when listening back to it, it reminded me of how Minnie Riperton used her upper register on her hit song ' Lovin' You.' I thought how ironic that her song was called 'Lovin' You' and my song is called, 'H.A.T.E.U.' - and both use that upper 'whistle register' as a major part of the melody. So it's sort of an homage to Minnie Riperton, a tribute to her since she has been so influential in my singing style."

The Minnie Riperton song also has a link to the album title. Carey explained: "I had written a song called 'Imperfect,' but it didn't make it onto the album. The lyrics of that song address the fact that the world puts so much pressure on us - especially on women - to be perfect and look a certain way, and that is impossible because nobody is perfect. Only God is perfect. I know I've tried to be a good person, but I am definitely no angel! But after I put this album together and decided to name it Memoirs of an Imperfect Angel. I remembered that the Minnie Riperton album that contained 'Lovin' You' was called Perfect Angel. So I felt in so many ways that it was meant to be."