When we’re so used to seeing the likes of our beloved “Arrested Development” and “Freaks and Geeks” terminated before their time, it’s easy to forget that even the best shows have an expiration date. The sixth season of “The Office” will premiere next Thursday, but I wish it wouldn’t.

It’s not that the fifth season’s subplots weren’t funny—think Michael Scott Paper Company or the introduction of Rolf, Dwight’s new best friend—it’s that they all feel like another way for the writers to stave off the inevitable. Sure, episodes like the absurd tour de force “Café Disco” are an occasional blip on the EEG, but they are growing less frequent. Whatever disease “The Office” has, it’s terminal.

By all accounts, “The Office” should not have succeeded in the first place. Channel 4’s “Peep Show,” a dark, quirky gem of a single-camera comedy, was remade for Fox in 2005—the same year that the first season of the “The Office” aired stateside—and was never commissioned beyond the pilot. More recently, a U.S. version of “Kath & Kim,” Australia’s Logie-winning favorite, enjoyed only a brief, critically disastrous stay on NBC last year. In retrospect, though, creators Ricky Gervais and Stephen Merchant seem to have stumbled upon one of the hardiest premises in television history; “The Office” has been successfully transported to France, Canada, Germany, and Chile.

The largely unimpressive pilot of the American “Office” had an almost identical script to that of the British premiere. Slough became Scranton, Tim became Jim, and in one memorable punchline, “Camilla Parker Bowles” became “Hillary Clinton.” It took a uniquely American episode—the all-around-genius “Diversity Day,” written by B.J. Novak ’01—to win us over. Best of all, we found the U.S. “Office” to be populated with wonderfully bizarre secondary characters, developed far more deeply than the few on the U.K. version. More of my favorite television moments involve Creed Bratton than any other character, on any show.

Back in 2001, Gervais and Merchant established a modest television timeline—two, six-episode seasons plus a Christmas special—that suited “The Office” perfectly, as it would “Extras,” their brilliant sophomore effort. And yes, the first season of the American “Office” also had six installments. The second? 22. Don’t get me wrong—the second season is probably the show’s best, and by the time the finale, “Casino Night,” aired, no one was complaining that we’d seen too many episodes that year. But by keeping this pace, they’ve racked up one hundred to date. American sitcoms are on growth hormones, and the results aren’t always pretty.

In particular, the ticking time bomb strapped to “The Office” has always been the development of Jim and Pam’s relationship. Remember the first season, when it was thrilling just to see Pam fall asleep with her head on Jim’s shoulder? What is there to look forward to now—Jim and Pam’s baby wryly acknowledging the camera in his sonogram?

Sexual tension is the life and death of sitcoms. “Cheers” was all Sam and Diane, and when it wasn’t, it was Sam and Rebecca, and when it wasn’t, it... wasn’t. Some of the same writers moved to “Frasier,” where they perfected the art of the slow burn. In the alternative TV universe where Niles and Daphne have sex and get it over with in the first season, they might have been raising a first grader by the time they actually kiss in season seven.

And it’s not that the writers of “The Office” haven’t figured this out. In fact, they’re all too aware of the problem. It’s clear that they’ve attempted the delicate act of shifting the show’s focus away from Jim and Pam, with renewed attention to the romantic misadventures of Michael and Holly, and Angela and... everyone. But once we’ve veered away from the Jim-and-Pam arc, the zaniness we love in the other characters actually works against them; there’s nothing to ground the show.

“The Office” is spectacular because it’s fundamentally based in reality. It’s not another show about eccentric, attractive young urbanites cohabiting an apartment disproportionate to their income. It’s about a boring workplace, a terrible boss, and a likeable couple falling in love. Its genius is in its simplicity. As great as Dwight and Andy’s budding bromance may be, the secondary characters aren’t enough to drive the plot. Without a solid footing, The Office has begun an inevitable decline into mediocrity.

So, next Thursday night at 9 p.m., I’m going to make popcorn and blow off any responsibilities I need to so that I can sit down and watch “The Office” premiere with my friends. And, if you asked, I’d probably still name “The Office” as one of my favorite shows on television, because it’s still good. But it won’t be for long.

—Columnist Molly O. Fitzpatrick can be reached at fitzpat@fas.harvard.edu.