Greenberg, Film Festival, Berlin

Greenberg is a delicately observed, very well acted character study that is undermined by the utter obnoxiousness of its main character. It is very hard indeed to care about Roger Greenberg (Ben Stiller), the dysfunctional anti-hero of the film: a man on the cusp of middle-age, bitterly disappointed by the way his life has turned out.

Roger has just reached his forties and is emerging from a nervous breakdown. As the film begins, he arrives in LA to house sit for his wealthy brother, who's off to Vietnam for a family holiday. Florence (Greta Gerwig) is the family's personal assistant: a woman in her mid-twenties who is also a lost soul. Inevitably, Roger and Florence begin an affair.

Noah Baumbach shoots the film in a very slow-burning way. Cinematographer Harris Savides holds individual shots for what often seems like a small eternity. Dialogue sequences are equally drawn out. The film-makers study their characters with an anthropological relish, as if by training the camera on them so closely and for so long, it will be possible to unveil their most secret desires and motivations.

Stiller's character has the same wired-up energy and aggressiveness that he brings to many of his comic roles. He is at war with a world that he thinks has dealt him a very unfair hand. In his spare moments, he obsessively writes cranky letters to newspapers, airlines or politicians, complaining about perceived injustices. The smallest provocation – a fellow diner laughing too loudly in a restaurant or a fridge without beer – can push him toward fury. He is a hurt and truculent figure.

In its own quiet way, the film is often funny and poignant. Years ago, we learn, Greenberg and his friends were in a band. They were on the verge of signing a deal... until Greenberg vetoed the idea. This is a source of regret but also, perversely, of pride. Greenberg clings to the notion that he was once, almost, a rock star. He is also under the illusion that he came close to marrying his old girlfriend (Jennifer Jason Leigh), another face from his past living in LA. That is not, though, at all how she sees it.

Rhys Ifans is likeable and laidback as Greenberg's "best friend," a recovering alcoholic himself trying to cope with the diminished expectations of middle age. Greenberg is so wrapped up in his own problems that he is oblivious to his friend's problems.

Baumbach's first film, The Squid and the Whale, had charm in abundance. A barbed comedy-drama about divorce, its observations were often as caustic as the ones found here but Jeff Daniels's turn as the egotistical novelist and Jesse Eisenberg's as the self-centred adolescent son were so likeable that you rooted for the characters anyway. Charm is the quality that this film most desperately lacks. It's not that Stiller gives a bad performance. He is utterly convincing as the needy, neurotic, bad-tempered Roger Greenberg but that doesn't mean that you want to spend any time with him.