Songfacts®:

• The Metzger brothers originally began performing their material in their teen years (or in Jack's case pre-teen). Here, they sing about that strange transition period between childhood and adulthood when they're trying to pull off the mature thing without actually feeling grown up.
  
  Feel like I'm gonna puke 'cause my taxes are due
  Do my password begin with a one or a two?
  Been a hell of a ride, but I'm thinking it's time to grow
  Bang! Bang! Bang!
  
  "We wrote 'BANG!' about the weird middle ground between being a kid and becoming an adult; a time when we're doing all the things adults are supposed to do, but we don't yet feel grown up," the Metzer brothers said in a press release. "The fact is, adulthood is bound to hit us at some point, so the plan we made in the song is to 'go out with a bang.'"
• AJR started off crafting the song with a mysterious horn beat in an attempt to create the feeling of a movie villain entering a scene. They then added the playful verses about "that weird time where you're not quite a kid anymore, and you're not quite an adult yet," which Ryan Metzger told American Songwriter is something that the brothers think about a lot.
• The voice that intones "here we go" and "metronome" on this song is familiar to anyone who has ridden the New York City subway: It's Charlie Pellett, the voice of the subway system - the one always telling us to "stand clear of the closing doors, please." It turns out, Pellett is a fan of AJR; when they found out, they recruited him for the song.
• AJR's musical craftsman, Ryan Met, put the orchestra together on his computer, adding strings and trumpets to the percussion (including a prominent piano) to create a unique sound. He says the song is "20% familiar, 80% something you've never heard before."
• The Se Oh-directed video shows AJR hosting a dice game. Each time the camera zooms in and out on the band members, the gamers have adopted a different look. "We wanted to approach the 'Bang!' visuals with a retro, Wes Anderson style," they explained. "Much like the song, we wanted to put AJR in this unpredictable new setting, watching these surreal characters dance around us."
• AJR shared a second video as the accompaniment to a highly choreographed hand-washing routine during the global coronavirus pandemic. "Too much time on our hands," the band wrote in the caption. "But never enough soap on our hands. Stay healthy everyone."
• On August 17, 2020, AJR released a remix (the "Ahhhaa Remix") with Hayley Kiyoko on vocals. The collaboration came about after Kiyoko heard the song, and her management got in touch. Ryan Metzger explained to Billboard:
  
  "She sent us her verse, and we got on the phone with her right away. We loved the verse. She has a great voice, and she's a super sweet person. Honestly, when anyone connects to the song and they wanna hop on it just on their own volition, we're happy to have them."
• AJR first started working on "Bang" while writing for their Neotheater album. Though they were excited about the track, the trio felt it was too theatrical for that record as it had more of a nostalgic vibe. After they'd completed the Neotheater cycle, the band picked up the song again. The Metzger brothers sped it up, added more trap drums and came up with the "Let's go out with a bang" concept.
• AJR hit upon the word "quinoa" as encapsulating the transition between childhood and adulthood.
  
  So I got an apartment across from the park
  Put quinoa in my fridge, still I'm not feelin' grown
  
  Ryan Metzger explained to Billboard why the quinoa line is so apt. "It's a terrible food. It's one of those things that we gotta start eating. It's a superfood. When we were writing the lyrics, we were trying to figure out how to encompass adulthood in one word, and it was quinoa."