IT'S ABOUT TIME writer/director Noah Baumbach wrote a full-fledged character study, because his attention to the details that make up a personality is peerless. Baumbach's last movie, Margot at the Wedding, relentlessly catalogued the anxieties and quirks of two estranged sisters—but while the depiction of family dynamics was razor sharp, Margot's characters were so generally unpleasant that by the time Jennifer Jason Leigh pooped her pants in the woods, it was hard to care how all that meticulously detailed moping would be resolved.

With Greenberg, Baumbach tempers his lacerating insights with a humor that recalls his excellent 2005 film The Squid and the Whale. Via its title character, Greenberg poses the question: Does everyone deserve to be loved? Even people who are really, really big assholes?

Roger Greenberg (Ben Stiller) is an unstable New York carpenter, fresh off a stint in a mental hospital, who's just relocated to LA to housesit for his brother. While he once wanted to be a musician, these days Greenberg is dissatisfied and sour, a curmudgeon who keeps up a running commentary of cynicism and bitterness disguised as humor, and thinks of himself as a real funny guy.

Soon after arriving, Greenberg makes a half-hearted move on his brother's assistant, Florence (the pretty, likeable Greta Gerwig)—despite all evidence to the contrary, he seems to think he's doing her a favor. Florence is self-deprecating and capable, vulnerable and pragmatic. Her clothes don't quite fit; she is, as Greenberg critically notes, "bigger" than his still-idolized ex-girlfriend Beth (Jennifer Jason Leigh); she's as close to a real girl as you're going to see on a movie screen anytime soon, and it's not at all clear why she's willing to put up with Greenberg's shit.

It's not until Greenberg hosts a last-minute pool party that we're given a glimpse inside his head—and, by extension, into Florence's. As he walks toward the pool with a tray of artfully arranged snacks, the phone rings—and Greenberg freezes, panicked and paralyzed by too much information at once. It's the first time the audience sees what Florence seems to have known all along: that beneath the insensitivity and abrasiveness is an anxious, fucked-up man trying very hard to keep his shit together. Suddenly their relationship makes sense: Florence needs someone to care for, and Roger needs care.

Greenberg changes very little over the course of the movie (his epiphany, when it comes, is trite: "Hurt people hurt people"), but the audience's perspective on him changes quite a bit, in a tidal shift that lends this perceptive movie surprising power and momentum.