When you break down the reasons that the Lonely Island have been so successful—their skill at flawlessly mimicking various pop music styles, their knack for shareable short-form videos—the comedy trio’s secret weapon may be the most overlooked: their abiding affableness. Satirists as prototypical nice Jewish boys (even if only two of the three members are Jewish), Andy Samberg, Akiva Schaffer, and Jorma Taccone made their name sending up celebrity culture and popstar ego, but they did it without leaving their targets burnt. Rewatch the Lonely Island’s best Digital Shorts, and you’ll notice that the punching bag is often the trio or their alter egos, such as Samberg’s clueless “Dick in a Box” lover-man. In their world, even eternal laughing stock Michael Bolton ends up looking kinda cool.

Popstar: Never Stop Never Stopping is far from a perfect film, but it may be the ideal delivery device for the group’s particular brand of pop-culture absurdity. Since breaking out in 2005 with the Saturday Night Live short “Lazy Sunday,” the Lonely Island have radiated a lot of geeky good cheer while seeming hip about it, making the inherent dorkiness of their white-dudes-doing-black-music shtick not just funny but resiliently fresh. In this new mockumentary, about a former boy-band sensation learning that his stranglehold on the charts isn’t permanent, the trio’s mockery remains as kind as ever. Deep down, they love the shallowness of the musical forms they lampoon—if they didn’t, they wouldn’t have been able to make so many great pop songs over the last decade.

Drawing plenty of inspiration from This Is Spinal Tap, the movie stars Samberg as Conner4Real, who was the charismatic phenom in the group the Style Boyz, which also included his Sacramento childhood chums Owen (Taccone) and Lawrence (Schaffer). But Conner’s solo stardom drove Lawrence into angry obscurity—he’s now a bitter farmer in the middle of nowhere—and forced Owen to become a glorified extra in Conner’s ridiculously lavish solo shows.

Directed by Schaffer and Taccone, Popstar follows a predictable path as Conner’s sophomore disc, CONNquest, gets ready to drop, quickly fading from the charts and leaving our vapid hero at an existential crossroads. The film’s title is a play on the recent music documentary/image-maintenance Justin Bieber: Never Say Never, but it’s typical of Lonely Island that Bieber isn’t really set up to be knocked down. Instead, Popstar is a gleeful smorgasbord of dopey jokes set in and around the pop music world, playfully goofing on the divas, the pretentious, and the pathetic hangers-on that fall into its orbit. It’s impossible to imagine any star watching this movie and thinking it’s making fun of him—the Lonely Island have always been so loving and nonspecific in their barbs that it’s clear they’re riffing on our shared affection for a particular target as opposed to our derision. (“Dick in a Box” and its sequels probably wouldn’t have been quite so beloved if we sensed that the trio hated Color Me Badd.)

There’s a tradeoff for the Lonely Island’s benign form of ridicule: Popstar is an exceedingly superficial gloss on all that ails the music industry. Written by all three Lonely Island members, the film recruits the trio’s famous friends—Questlove, Usher, Nas, Mariah Carey, Simon Cowell—to play themselves as talking heads discussing Conner’s progress, humorously exaggerated in their praise of this utter lightweight. No joke draws blood, or elicits even a wince. (It’s telling that the only really vicious attacks are leveled at TMZ, which is universally loathed—particularly by celebrities, which the Lonely Island and their pals are.) As in their videos and songs, Popstar reserves most of its meanest stingers for the guys themselves—particularly Conner, who’s a relatively harmless egomaniac. (At worst, he’s a shameless pilferer of black musical styles, an oblivious homophobe, and a dude who doesn’t understand that nobody wants a love song that ties nasty sex with the killing of Osama bin Laden.)

Popstar’s overriding tone is that of chummy insider-ness, Samberg and his crew affectionately roasting an entertainment-industrial complex they know intimately. But while that might feel insufferably cozy, the trio rely on their usual pose, which is to position themselves as the nerds at the party. In their SNL music videos, it was always T-Pain, Rihanna, or Akon who was the cool member of the duet, with part of the humor being that Samberg’s doofus stood out amidst the pop-star fabulousness. Likewise, Conner may be a star, but Samberg plays him with such adorable vulnerability that his cosmic comeuppance is both unsurprising and slightly depressing. (Like the bozo head-bangers at the center of This Is Spinal Tap, Conner isn’t that evil, so we don’t really relish his fall from grace.) For all their success as songwriters and video-makers, the Lonely Island have managed to remain seemingly ordinary, and as such Popstar’s best running joke is the juxtaposition of these three geeks alongside Snoop Dogg, Adam Levine, and other actual stars.

If Popstar is a solid encapsulation of what made the Lonely Island great, it’s also a sign that the trio’s best days are probably behind it. Starting with their 2009 debut album Incredibad, the Lonely Island have demonstrated an impressive ability to meld pop hooks, cultural commentary and great jokes into dynamic three-minute tunes, parodying and paying homage to their musical targets simultaneously. The Wack Album, released in 2013, was the group’s spottiest, and Conner’s songs in Popstar don’t peak as high as a Lonely Island fan might wish. Likewise, there’s a sense that this movie says just about everything these guys will ever need to say about fame or the music industry: the two subjects that have been their bread and butter since 2005. If that’s the case, then this is a fine finale. They go out not at the height of their powers, but with their inexhaustible affection still happily intact.

Grade: B

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Grierson & Leitch write about the movies regularly for the New Republic and host a podcast on film, Grierson & Leitch. Follow them on Twitter @griersonleitch or visit their site griersonleitch.com.