In 2014 “Ain’t It Fun” became the biggest hit in the band’s history, peaking at No. 10 on the Billboard Hot 100.

When asked by the St. Louis Post Dispatch about the song’s success, Hayley said:

I’m supersurprised. It should always be a surprise. I don’t think you should ever assume a single is going to be your big hit or be a success. This song by far has shocked all of us."

Hayley wrote on the band’s LiveJournal that the song is a message to anyone who sometimes forgets that he or she isn’t the center of the universe, including herself.

“Ain’t It Fun” is the first Paramore song to include a gospel choir – something Hayley and Taylor thought would be cool but never really envisioned doing. Hayley told Radio.com:

I grew up on gospel. I love gospel and I think I never thought it would mesh at all with what Paramore would ever do. But luckily on this album, we were a lot more openminded…we weren’t as closed off. … They put so much soul and so much feeling into their sound that makes it real and raw. I actually cried like three times just hearing these people sing our song. It was so cool.”

That was one of the reasons Hayley said this song surprised her the most. It came about during a period when the band was having trouble making music for the new record, and Taylor was just jamming trying to make something that sounded like the Dutch Uncles, who he had recently been listening to. He never expected it would be a Paramore song. Hayley said she thought it sounded like Siouxsie and the Banshees meets Paula Abdul.
They talked about this when they were guests on Fuse’s Trending 10.

That song sort of happened by accident. I remember Taylor was working on the music, and you didn’t think it was a Paramore song.” -Hayley

I thought it was going to turn into this weird song that nobody would ever listen to. It was going to be, there’s this indie band I listen to that I was really inspired by, and I was going to make this really ethereal, weird song. Hayley heard it and said, what is that? And it turned into this funk, gospel, pop song. And I was like, how did that go from that to this? That’s the joy of being in a band. You have one thing, and collectively it all turns into something else.” –Taylor

At first, Hayley and Taylor just layered their voices over and over again, as if it were a gospel choir. “Then, six months later, we were actually in the studio with one,” Hayley told HelloGiggles.com. “That’s the best example of how for this record, we flew by the seat of our pants. We did what we thought could work, and when we followed that inspiration, it always turned out okay, into something we love.”

Hayley has said this song is the closest any Paramore track has been to her work with The Factory, a funk cover band she and Jeremy Davis were in prior to the formation of Paramore.

Alternative single artwork: