There are two stories intertwined in Greenberg, Noah Baumbach’s painful, grimly comic portrait of bourgeois dysfunction in Los Angeles. One involves a 40-year-old failure, angry, acerbic, and self-sabotaging, who lurches back into his friends’ lives after a stint in a mental institution and staggers from one debacle to another. The other one made me depressed.

The failure in question is the title character, Roger Greenberg, played by Ben Stiller as a dark variation on the wound-too-tight types we’re used to encountering in his comedies. Greenberg isn’t having a midlife crisis, exactly, because that would require him to have a life to begin with. “I’m trying to do nothing right now,” he tells people, but it’s pretty clear that he’s been doing nothing for a long, long time — since his mid-twenties, to be precise, when he persuaded his then-bandmates to turn down a record deal, sacrificing their hopes of musical success to his fear of selling out, or growing up.

The bandmates grew up anyway — marrying and divorcing, having children and building careers — but 15 years, a move to Brooklyn, and a breakdown later, Greenberg is still sticking to his guns. No adulthood for him: He’s learned carpentry, forgotten how to drive, and thrown up a Maginot Line of defense mechanisms against the reality that life has passed him by. (In his spare time — and it’s all spare time — he writes pretentious letters of complaint to Starbucks, Mayor Bloomberg, and various corporations.) Back in L.A. to house-sit for his prosperous brother (Chris Messina), who’s taken his family to Vietnam for six weeks, Greenberg looks up his band’s guitar player, Ivan (a mournful Rhys Ifans), makes an unsuccessful pass at an ex-girlfriend (Jennifer Jason Leigh), and strikes up an awkward romance with Florence (Greta Gerwig), his brother’s twentysomething personal assistant. He’s groping toward human connections — but he’s holding out a pricker bush, mostly, rather than a hand.

If this sounds like a difficult protagonist to spend a movie with — well, welcome to the land of Baumbach, where misanthropy abounds, conversations slash like daggers, and all families seem inherently unhappy. Like The Squid and the Whale and Margot at the Wedding, Baumbach’s last two features, Greenberg doesn’t care if you like its characters; it just wants you to believe in them, and recognize aspects of their pathologies in your friends and neighbors — or, worst of all, in yourself.

Unlike those movies, though, Greenberg has an arc that bends toward a kind of happiness for its abrasive anti-hero. Stiller’s character doesn’t deserve love, but unexpectedly, he gets it. His May–August relationship with Gerwig’s Florence is a morass of missed signals, awkward encounters, and semi-abusive dialogue (from him, to her). Yet it doesn’t end in tears: Instead, she tolerates him, forgives him, and nurtures him, offering the possibility of a real human connection, and a ladder out of darkness.

And this is where the depressing part comes in — in her story, not in his. Gerwig’s Florence is a sweetheart, and a mess. She apologizes too much, falls into bed with too many men, has no idea what she’s doing with her life, and lets Greenberg treat her in ways that no kindhearted twentysomething should be treated by a slightly twisted older man. Their courtship, which the movie effectively asks the audience to root for, seems to offer vastly more to him than it does to her. She’s all give, and he just keeps on taking.

There’s a long tradition in cinema of unlovely men ending up with women who are far too good for them, of course: Think of Helen Hunt falling for Jack Nicholson in As Good as It Gets, or Katherine Heigl stooping to wed Seth Rogen in Knocked Up, to pluck a pair of recent examples. But the problem with Florence isn’t that she’s too good for Greenberg, exactly. (She’s certainly no moral paragon.) It’s more that she’s too vulnerable for him, too easily wounded and manipulated. Her presence makes his life better, but it’s hard to imagine his presence doing anything but making her existence worse. By falling into orbit around his dark star, she seems to be signing her life away to subjection and misery — and the audience is expected to be happy about it.

“Hurt people hurt people,” Stiller’s protagonist says at one point, a line that could serve as the epigraph for all of Baumbach’s work. But in Greenberg’s relationship with Florence, I’m pretty sure I know who’s going to end up getting hurt the most. Baumbach wants to use their romance to let a ray of light into a characteristically dark tableau. But as the movie drifted toward a semi-uplifting ending, all I could think was, “Honey, he’s going to eat you alive.”