This song was originally uploaded onto Niconico on May 2nd, 2011 and YouTube on September 5th, 2017. It has since reached over 6,000,000 views on Niconico and 9,000,000 views on YouTube, becoming one of wowaka's most popular songs and making it into the Hall of Legend.

A popular theory for this song is that it is about wowaka's dissatisfaction with the VOCALOID community. The theory explains that while wowaka's songs have seen great success, the success is under Hatsune Miku's name rather than wowaka's, invalidating the hard work he put into his own music. This theory uses wowaka's absence after releasing Unhappy Refrain and its eponymous album as evidence towards wowaka's said dissatisfaction, as well as the lyrical content being about feeling tired and wanting to quit.

However, wowaka has stated in an interview that his disappearance from the VOCALOID community was from burnout and pressure to stick to a formula instead being free to make what he wants. In this same interview with DECO*27 they talk about how people were approaching the VOCALOID community with the mindset of fame instead of an appreciation for Hatsune Miku and the culture surrounding it. For about half a year before releasing Unhappy Refrain, wowaka had minimal social contact, had all his meals delivered and started drinking. After Unhappy Refrain, wowaka started talking to Ygarshy, Yumao and Shinoda which ended up forming the band hitorie. During the time in this band wowaka still wanted to write VOCALOID songs but felt the need for someone to give him a reason, Re:Start ending up being the push needed to write Unknown Mother Goose.[1] From this interview and the lyrics it can be interpreted that Unhappy Refrain is about how wowaka felt restricted and burnout in the VOCALOID community and needed a break to focus on himself.