When did American movies get so sexless? In movie after movie, it's the same: a man, a woman, discreet lighting, no bad angles; as with happy endings, orgasms are inevitable. For the most part, you'd have to go back to the '70s to find a scene in which two adults hump without the gauzed-over niceties; if it's a gay movie, you'd have to retreat to the '80s. The irony is that while modern movies tend to be willfully tame, the sex scenes function the same way that the money shot functions in porn: as the payoff for everything that's come before, our reward for all the foreplay chatter. Sex scenes these days are a time-out not just for the characters but the audience: a chance to take a break from the story and check out the jiggle factor of the leading lady's tits, or to snicker at some aging idol's mortified rear end. As soon as the plot revs up again, though, sex gets banished from the narrative. It says more than we probably care to know that about the only time sex gets integrated into the plot of a movie is when it's pathological, as with a Paul Verhoeven thriller or a slasher picture, films in which sex isn't just rough, but lethal.

No one gets killed in Neil LaBute's Your Friends & Neighbors, though there are plenty of lethal passions in evidence from the very first scene, in which actor Jason Patric, drenched in sweat, pantomimes sex alone in his bed. A beautiful hater and dedicated sack artist, Patric's character, Cary – who, like all the characters in the movie, is named only in the credits – has committed himself to perfecting his bedroom technique, primarily to wreak havoc on women. (He doesn't just tape his pillow talk for playback, he clocks it with a stopwatch.) Although the character has the dead eyes of a killer, his technique seems to have worked, even if we have to take his word for it. LaBute never shows Cary literally screwing – we see him shrieking at some blond huddled in his bathroom and, later, delivering curious comfort to another partner – but the writer-director does let the character talk his dirty, mean talk, mainly to himself and the two friends with whom he occasionally socializes: Barry, a hapless married man played by Aaron Eckhart, and Jerry, a college theater professor in a salt-and-pepper goatee, played by Ben Stiller.

Barry has just moved into a house with his wife, Mary, played by Amy Brenneman, while Jerry lives with Catherine Keener's advertising copywriter, Terri, a fierce, restless woman of the kind that doesn't often make it into American movies without an ice pick in hand. Rounding out the group is Nastassja Kinski as Cheri (LaBute no doubt thinks giving the characters rhyming names is cute, but it's the kind of gimmick that underscores a penchant for cleverness over meaning), a gallery worker who enters the group by way of an affair. But before she's wedged into the film, what gets the story going is Jerry's sudden, unsolicited come-on to Mary in her own living room while their unsuspecting partners are in the kitchen getting dessert and coffee ready. Coordinated in a giggled hush, that proposal is the first equation in a calculus of desire in which lovers are added, subtracted, multiplied and divided, relationships begun and ended. And while there's nothing particularly remarkable about the various intersecting subplots and character motivations – familiar, really, from any number of daytime soaps – what is remarkable is the absolute cool with which LaBute charts his story. Like Patric's character, the director has the soul of an assassin.

Your Friends & Neighbors is the first American movie in memory where sex isn't just a dividend, something, say, to prop up a sagging plot, or sales in the foreign market. It actually has something to do with the rest of everyday life. The film itself isn't remotely sexy, but it is filled with sex – sex talk, sex sweat, sex cruelty. The characters aren't always fucking (usually they're not), but when they're out of bed they're either obsessing over the sex they did have or most often didn't. The men function as uneasy allies in what can only superficially be called a war of the sexes – there's too much equal-opportunity malevolence to qualify for war – while the women tend to react to the men defensively, and be more sentimentally realized. Although it's hard to gauge where LaBute stands, he's not entirely liberated from cliche: He saves his nastiest, zingiest lines for the men and the more cryptic emotions for the women. Some of this has to do with the casting. While Eckhart and Brenneman are both tagged as losers, she brings a depth to her pathos – and a glint of malice – that he never summons. Keener and Patric play parallel types, his and hers predators, but while he remains one-dimensional, a sexed-up Terminator, she could have stepped out of a Mary Gaitskill story. All angles, with a hard, sneery mouth, Keener is terrific as the film's designated snatch, a woman who steps on a man's sentences and asserts fucking is fucking, not sharing and caring. It's a great role made greater by an actor who never loses sight of her character's humanity.

If only the same could be said for LaBute. Your Friends & Neighbors is a huge leap forward for the director, whose first film was In the Company of Men, but it's disappointing nearly as often as it's enlivening. LaBute has a background in theater (he's written a number of plays), and he hasn't grasped that certain theatrical devices – quasi-Brechtian hooks, exaggerated types who play large rather than intimate – don't necessarily translate when blown up for screen. Patric's Cary, who wears a white lab coat and does something unspecific and slightly menacing in a medical office, is the most extreme character in the film, but he's also the least recognizably human, an upmarket variation on the misogynist Eckhart played in LaBute's debut. A minor cause celebre when it was released last year, In the Company of Men, a film about two corporate types who seduce a woman to break her heart, inflamed critical attention for its writing and audacity. Despite the crypto-Mamet rhythms of its dialogue, the movie is crudely made and groaningly obvious; it panders to a liberal audience who want their sexual politics delivered without the benefit of dialectics.

Your Friends & Neighbors isn't a triumph of dialectical thinking, but it does offer up a world-view that is infinitely more complex than either LaBute's first film or much of current American cinema: No one is nice in the movie, no one justifies her acts of unkindness with psychology or by dredging through her childhood, no one is redeemed or redeemable, no one is saved. Things happen, including unhappiness. That may not sound like much – and certainly it isn't enough for LaBute to finish his movie – but these days, it's as close to radical, genuinely personal filmmaking as most of our directors dare to get. To an extent, his refusal to acquiesce to a commercial imperative such as the sure-fire happy ending (Hollywood's version of the multiple orgasm) is what makes the film seem like such a throwback. Your Friends & Neighbors outwardly recalls movies such as Five Easy Pieces and Bad Timing in its depiction of male self-loathing, but in some ways it scans emotionally closer to Sam Peckinpah's sordid freak-out, Straw Dogs. (Women's lib made for some fascinating male anxiety.) LaBute's not as talented as Peckinpah – he has the visual equivalent of a tin ear – but he has a similar way of getting under your skin. I can't remember another recent movie that I liked so uncomfortably.

Not that LaBute doesn't have a ways to go. He's still learning what to do with the camera (the cinematographer here is Nancy Schreiber, who livens up LaBute's self-consciously mannered choreography), and he has a belief in his own cleverness that could prove debilitating. Mainly, though, he could use some gentleness. LaBute's cruelty can be very, very funny, but too often it's a sour kind of funny. Mean is easy; compassion is tougher. LaBute is one of the most exciting young American writer-directors we have – he's the smart Hal Hartley – and while he doesn't have Hartley's intuitive visual sense, when his characters speak they're doing more than rattling the bars in the filmmaker's prison house of language. They're investing life in their words, and in their reason for being. When they're not – as in a scene in which the nicest character in the movie mocks her lover's impotence – you can feel LaBute losing faith. He sells out his characters too easily, and grubs for the audience's attention with jokes that simply shock instead of waking us. He'd rather make us wince than feel or think, which is why the film's end, a cockeyed coda, isn't just ridiculous, it's a cop-out. Up till then, though, Your Friends & Neighbors is the most interesting game in town, and one of the best American movies you'll see all year.

LA Weekly