In their ongoing effort to explain why the Swedes are so good at making pop, Alex and Jordan dive into the creation of “Dancing Queen.” (Spoiler: It might involve working their recording engineers to the brink of exhaustion.) They also touch on the lengthy writing process for the song, its long-lost verse, its debut before Scandinavian royalty, why it was banned in New York City, and how it inspired everyone from Blondie and Elvis Costello to Nirvana and MGMT.