Television is finally a respectable, aesthetically valid medium, critics assure us. From "The Sopranos” and "The Wire" to "Game of Thrones” and "Mrs. Maisel," TV now merits serious analysis, substantive engagement, and a million think pieces.

No one, though, remembered to tell CBS hit "The Big Bang Theory," which airs its final episode ever Thursday night. For 12 years, the show has stood resolutely off to the side of the quality television zeitgeist, snickering and snorting and, at its height, pulling in 20 million viewers an episode.

For 12 years, the show has stood resolutely off to the side of the quality television zeitgeist, snickering and snorting and, at its height, pulling in 20 million viewers an episode.

Newer sitcoms like Netflix's "Santa Clarita Diet" have embraced film production values, edgy content and virtuoso acting turns. Meanwhile "The Big Bang Theory" has slouched along like the sitcoms of yore, with an irritating laugh track, sets that look like sets, unadventurous three-camera filming and repetitive gags about sex and nerds. If we are living in the era of peak TV, than this is a show that insists on nestling in the trough. You could see that as cowardly or lazy, perhaps. But the show's refusal to try for quality also speaks to what quality is, and what its limits are.

Because "The Big Bang Theory" doesn't just ignore its critically acclaimed, slicker peers. It also comments on them. The series is obsessed with cultural anxiety; it jokes compulsively about the connection between aesthetic investments and social status. It invites you to sneer at its characters, even as it insists that to sneer at others is inevitably to be sneered at oneself. If "Game of Thrones" is a show for critics, "The Big Bang Theory" is a show that's in some ways about them. Which is part of why so many people loved it. And why critics loved to hate it.

Even if you're embarrassed to admit it, you probably know the basic plot of "The Big Bang Theory." Maybe you caught a re-run or five while channel surfing. Or bored at the doctor’s office. (Or maybe you’re actually a fan — don’t worry, we won’t tell anyone.) In any case, Penny (Kaley Cuoco), a waitress who hopes to be an actress, moves to a Pasadena apartment across the hall from two physicists, Leonard Hofstadter (Johnny Galecki) and Sheldon Cooper (Jim Parsons). She's sexy, popular and not very smart. They're nerdy, clueless and have stratospheric IQs. Hijinks ensue.

The show's main joke is the hilarious contrast between nerds and normies — a contrast which it insistently illustrates through the characters’ contrasting cultural obsessions. Leonard, Sheldon and their friends Howard (Simon Helberg) and Raj (Kunal Nayyar) play video games, read comic books and have orgasmic experiences when the new “Star Wars” film debuts. Penny, in contrast, likes sports and wine and knows who the Rolling Stones are.

"The Big Bang Theory" adores the silliness of its brand of culture commentary — which puts critics of the series in an uncomfortable position.

But these cultural interests are more than just hobbies — they're markers of competence and social hierarchy. Everyone in the show is mocked both for not knowing enough and for knowing too much about nerd culture, mainstream culture, both and neither. Penny is ridiculous because she doesn't know the difference between Green Lantern and Green Arrow; Leonard is ridiculous because he does. Leonard's massive make-up kit for Comic-Con Star Trek cosplay is impressive enough that Penny wants to borrow it. But dressing up as the Enterprise crew also gets the gang bullied and sneered at by random passers by. Cultural passions confer mastery and expertise. But they also open you to ridicule.

That makes the show sound mean-spirited and cramped, and sometimes it is. But it's also often about a group of disparate characters who accept that they can be friends despite not sharing the same interests — or even better, unexpectedly discovering that they do.

One of my favorite gags occurs in an episode where Sheldon's girlfriend Amy Farrah Fowler (Mayim Bialik) and Howard are driving together trying to come up with something to talk about. They make awkward attempts at uncomfortable conversation, until they suddenly realize that they both love Neil Diamond. They spend the rest of the episode belting out duets of "Cherry Cherry" and "America" — two nerdy Jewish actors on a critically panned show thrashing around to the music of an (often panned) Jewish singer. Speaking as a nerdy Jew, it's glorious.

"The Big Bang Theory" adores the silliness of its brand of culture commentary — which puts critics of the series in an uncomfortable position. To sneer at "The Big Bang Theory" is to participate in the interpersonal dynamics of "The Big Bang Theory." If you declare, "How can people like this stupid, tedious show?" then suddenly you're on that unconvincing set with Penny, asking how on earth Sheldon can be so obsessed with trains, or in the comic store with Leonard laughing at the guy who likes Archie comics instead of superheroes. When you're proud of watching "Game of Thrones" instead of "The Big Bang Theory," you've become one of the nerds you feel so smugly superior to. How is a think piece on Daenerys different, really, then launching into a verse of "Sweet Caroline"?

This isn't to say you can't criticize "The Big Bang Theory." The show has gradually recalibrated some of its sexist dynamics, balancing Penny's dumb blond routine with scientists like Amy Farrah Fowler and Howard's significant other, Bernadette (Melissa Rauch). But it's still heavily reliant on stereotypes. Raj, who in the first seasons can't speak when a woman is in the same room, plays into clichéd notions about emasculated South Asian men, as just one example. And the jokes have gotten less funny, especially in the last seasons. The actors seem bored, barely able to muster up their over-determined double takes.

But you don't have to love the show, or even like it, to acknowledge its accomplishments. At a time when television has become the go-to medium for highbrow cultural consumers, "The Big Bang Theory" has been the smartest lowbrow kid for over a decade, generating laughs via the very dynamics that were supposed to render it obsolete. The critical disdain and indifference the show has experienced is its longest, most obsessive running joke, on itself, but also on its detractors. After 12 years, "The Big Bang Theory" gets the final "Bazinga!"