"My Happy Ending" is a song by Avril Lavigne, written by herself and Butch Walker for her second studio album, Under My Skin. It was released as the album's second internationally released single in 2004 and became Avril's fourth most successful single. It peaked higher than "Don't Tell Me", the album's first single. In the United Kingdom, it reached the top five; in the United States, it peaked at number nine (staying in No. 9 for 4 weeks). Structurally, the song is written in 4/4 style and has a repeated hook in both the chorus and in the intro and outro.
The RIAA certified "My Happy Ending" platinum in January 2005, making it Lavigne's second platinum single after "I'm with You" (2002). Allmusic highlighted the song as one of the most significant post-grunge songs of all time.
The music video for "My Happy Ending" was written and directed by MTV and Grammy winner Meiert Avis. It was shot on location in Bushwick, Brooklyn and Harlem, New York City. The video begins with Lavigne running down a street and entering a cinema, where she finds the film playing is a montage of her memories concerning a specific relationship she had. At first, the memories (shown in full color) are happy, depicting Lavigne at the park with her boyfriend, as he hands her a flower and they laugh together. They are also shown goofing off inside a laundromat. However, as Avril sings "so much for my happy ending," the memories start losing color. Lavigne and her boyfriend lie in bed together, as she looks at him and he (obviously reeling from a disagreement) stares blankly away. The relationship culminates during the song's bridge inside a grocery store, where her boyfriend antagonizes her, insisting that he talk to her. He grabs her and tries to pull her into his embrace. Fed up, she turns and pushes him away. She proceeds to run out of the grocery store and down the street (from the beginning of the video), and to a guitar shop where she grabs a guitar and walks to the roof of the building, where she is seen performing with her band. There, she walks past her unapologetic boyfriend without looking at him. The theater film tears and the memories end, leaving the final seconds of the video as a close-up on Lavigne in the theater as she tries to decide if the break-up is happy after all. In the end, three other girls witnessing in the restaurant leave with Lavigne who know about the breakup as they befriend each other.
Avril said of the video: "It's about a relationship that doesn't work out, and having to say goodbye to all of the memories and... all that stuff." When asked if the video for "My Happy Ending" actually contains a happy ending, Avril said: "I don't know if the video has a happy ending. It kind of depends on how you look at it? In one way, it is because me and 'the guy' in the video aren't together anymore, and I think that's a better thing."