Starting with a bombastic series of orchestral stabs fading into a dramatic yet soothing combination of organ, wordless choirs, and random samples, "It's a Sin" is the Pet Shop Boys at their most self-consciously theatrical and huge during their '80s days. Songs like "Left to My Own Devices" and "I Wouldn't Normally Do This Kind of Thing" would find their own particular métier, but "It's a Sin" is strident and cutting through and through. Neil Tennant said in a later interview that the song was always "meant to be kind of big and funny and camp," and certainly the killer lead melody, swathed in huge amounts of echo and endless layers of keyboards, calls up a show tune gone crazily weird, disco's metadrama gone splashy and icy at the same time. With Chris Lowe's exquisite music running at full blast, Tennant's delivery is a wonder with his trademark thin, high vocals of the time carrying the tune effortlessly, putting on a true show. There's no questioning the cool outrage Tennant felt over his strict Catholic upbringing, though, which underpins the song. Samples from church services and Latin masses crop up throughout, even as Tennant sums up the hard balance of desire and guilt tormenting his character: "Father forgive me/I tried not to do it/Turned over a new leaf/Then tore right through it."