The pivotal moment in Neighbors comes near the end of its second act, as married couple Mac (Seth Rogen) and Kelly (Rose Byrne) begin to bicker over their prank war with the neighboring frathouse going too far. Mac loudly demands that Kelly become the nagging shrew of a thousand crappy comedies, to be the Leah Remini to his Kevin James, and whip him into shape. Kelly, who throughout the movie has been just about as wild and devious as her husband, shouts back that she has absolutely no interest in doing so. This film was not written by Rogen nor produced by Judd Apatow, the master of the man-child comedy. But it still feels like a watershed moment for them.

Like so many young-skewing comedies of the era, Neighbors is about that melancholy moment when one realizes that partying and having stupid fun isn't as fulfilling as it used to be. It opens on Mac and Kelly as new homeowners and parents, but while they immediately react to the frathouse next door with caution, they still go over there and have a good time. When things quickly turn sour, they become obsessively focused on their war with Delta Psi; it's when it dwindles that they realize they'd been using it to distract from the transitional moment they're caught in.

What makes the movie so charming is that Kelly is going through this alongside Mac, rather than dragging him into adulthood with their (adorable) baby in her other arm. While everyone involved in Neighbors is doing sterling work, it's Byrne who walks away with the film by making Kelly a well-rounded, conflicted person, rather than the film's fun cop who has to tell everyone the boring truth. Her chemistry with Rogen is easy and natural, as is her appetite for insanity, and she doesn’t feel like a prop in the film’s grossest moments (involving breast milk) or its most salacious (involving girl-on-girl makeouts).

The film's other surprise is Zac Efron, although it's not like he's really proving his comedic chops here. Neighbors essays the increasingly dangerous and often brutal pranks these otherwise reasonable people play on each other, but to understand, just take one look at Delta Psi president Teddy's face. There's not much backstory on offer here, nor does there need to be. We get that Teddy is hardly a model student and that the (largely meaningless) reputation of his frat is all he cares about. Really, he's suffering through the same transition as Mac and Kelly, just ten or so years earlier, and with less hope of an exciting future.

Teddy could be just annoying or purely villainous, but there's something about Efron's steely performance that makes him darkly sympathetic. Any attempt to have him be directly comic flops—there's an improv-y scene between Teddy and chief bro-friend Pete (Dave Franco) that sees them trying to one-up each other's lame sexual innuendos. That stuff killed in The 40-Year-Old Virgin when it was being done by pros, but it feels painfully awkward here. It's also totally unnecessary. Efron is at his funniest when he's at his most serious, because that anyone would take these things so seriously is the best joke of the movie.

Neighbors is the latest Nicholas Stoller film to find surprisingly dark channels in a typical R-rated comedy. Forgetting Sarah Marshall did not shy away from its hero’s uncomfortable sexism and irrational behavior in the wake of a breakup; The Five-Year Engagement explored similar tensions, albeit with less success. Neighbors, which Stoller did not write, is far more fun and freewheeling than those movies, and at no point does Mac and Kelly’s union seem to be in any doubt. But Stoller makes the frathouse parties as intense as he can, jacking up the thumping soundtrack and cutting wildly. It’s at times exhausting to watch, although perhaps that’s an indication that my sympathies and energy levels lie more with the new parents than the hyperactive frat brothers.

Neighbors is stocked with the usual strong supporting cast—Ike Barinholtz (who has easily the film’s biggest laugh line) and Carla Gallo are warring divorced friends of Mac and Kelly’s; Christopher Mintz-Plasse, standup Jarrod Carmichael and Submarine’s Craig Roberts fill out the frat; Hannibal Burress makes the first of what will likely be many bit part appearances in such films as a laconic cop. The whole thing breezes by in a very agreeable 97 minutes (a lesson Stoller perhaps learned from the endless Five-Year Engagement) and does its best to include as many envelope-pushing jokes as possible. On top of spurting breast milk, there’s broken bones and a staggering amount of dick jokes, an apt reflection of the prevailing, sweaty mood of every frat house. But your attention finishes where it began—Byrne and Rogan’s winsome chemistry and happily grounded life lessons.