When the docuseries The Beatles: Get Back premiered last month, the Internet came through with a host of great memes about toast, Ringo Starr's flatulence, and George Harrison’s decision to leave the band. But the funniest of the bunch, created by writer Ben Rosen, pokes fun at Paul McCartney and his 1979 holiday staple "Wonderful Christmastime."

In the first of the meme’s four panels, McCartney asks the other Beatles if they can try his song about "simply having a wonderful Christmastime." When they tell him no, Paul says to himself, “I need to break up The Beatles.”

The meme works because “Wonderful Christmastime,” which McCartney wrote and recorded about a decade after the events depicted in Get Back, is a song that people love to hate. It’s also a song that people love to love. In 2011, Rolling Stone readers voted it the ninth best Christmas song of all time. (No. 1 was John Lennon’s “Happy Xmas (War Is Over).”) More recently, publications like Esquire and Slant have declared Macca’s synthed-out yuletide ditty one of the worst Christmas songs of all time.

Why does the song provoke such strong reactions? It may have something to do with the structure, or lack thereof. According to musicologist and performer Nate Sloan, co-host of the acclaimed podcast Switched On Pop, “Wonderful Christmastime” is "simple to a fault," as it consists solely of verse and chorus sections.

"It moves through the verse section of the song faster than a sleigh with no brakes," Sloan tells Mental Floss. "Before you know it, 'that’s enough' and we’re off to the titular chorus. It’s like you’ve barely finished your eggnog before someone shoves a plate of ham in your face.

"The only variation comes with the bridge section, ‘the choir of children sing their song,'" Sloan continues. "Is their song ‘ding dong?’ Or are bells ringing simultaneously? Either way it’s not the most inventive passage.”

If the melody and structure are basic, Sloan says, the song’s harmonic patterns are “diabolically complex.” Take the chorus. "Those chords are deep and jazzy, drawing on the rich harmonic vocabulary of 1940s and '50s pop music, when most of the current holiday canon was composed," Sloan says.

Part of people’s dislike for the song might also stem from the instrumentation. McCartney recorded “Wonderful Christmastime” all by himself using the Sequential Circuits Prophet-5 synthesizer, a then-new device that would later be used on hits like Hall and Oates’ "I Can’t Go For That." As Sloan points out, it’s fairly unusual to hear synths in holiday songs.

"Usually the timbral palette leans toward the acoustic, and by extension, nostalgic, sounds of ‘real’ instruments,” Sloan says. “When you do encounter synthesizers in a Christmas song, as in ‘Last Christmas’ by Wham!, they tend to be lush, sustained ‘pads’ that lend an almost orchestral sensibility to the track. On ‘Wonderful Christmastime,’ the Prophet-5 by contrast is staccato, harsh, and tinny—it’s a bold choice by McCartney, and a testament to his experimentation with an instrument that would soon become an industry standard but was less than a year old at the point when he recorded ‘Wonderful Christmastime.”

Composition and sonic texture are important, but with a song like “Wonderful Christmastime,” lyrics are also crucial. Compared to something like Lennon’s “Happy Xmas,” “Wonderful Christmastime” feels light and inconsequential. Instead of asking a deep question like, “So this is Christmas, and what have you done?,” McCartney looks around the holiday party and decides, “We’re here tonight, and that’s enough.”

“The lyrics are direct, simple, and universal—all key qualities of a good pop song, and as true of a good Christmas song,” Sloan says. “Repetition is key here, as well. Over the course of the song, you hear the title phrase 17 times, so by the time you’ve finished listening that lyric is burned into your synaptic pathways for all Christmas future.”

“Wonderful Christmastime” is certainly hardwired into the collective memory. In 2010, Forbes reported that the song earns McCartney between $400,000 and $600,000 per year. When asked to explain the song’s enduring popularity, Sloan cites McCartney’s ability to “channel a sense of childlike wonder in his music.” And for the record, Sloan is a member of the pro-”Christmastime” camp.

“In the increasingly rigid annual rotation of holiday songs, ‘Wonderful Christmastime’ stands out for its timbral palette and inventive chord structure,” he says. “And for that reason, I find it a welcome relief from the familiar strains of Mariah and Bing.”