The best thing about Take This Waltz—writer/director Sarah Polley's devastating study of marriage, desire, and the war between marriage and desire—is the way it moves through time. A lot of directors get stuck when moving the narrative forward by a matter of weeks or even days. In film, it's almost easier to skip decades or centuries than it is to skip a few seasons. But Waltz spans a year or so in the relationship of a young married couple named Lou and Margot (Seth Rogen is the affable husband, Michelle Williams is the sensitive wife) as Margot develops a crush on Daniel (Luke Kirby), the artist who lives across the street. In a recent phone interview, Polley says Waltz is about "what you do with the passage of time," and in her hands, the passage of time appears to be an effortless thing.

Waltz challenges its viewers by testing their patience. Polley employs tweeness as a tool; Williams and Rogen are the kind of young, hip couple that make imaginative jokes out of everything, like an improv class attended by precocious children. Their home decor—thrift finds and kitschy magnets all over the refrigerator—feels more precious than functional. And when Margot meets Daniel, she tells him she hates airports because she's—gag—"afraid of connections."

Polley isn't herself a twee or precious director; she just happens to be making a film about people who occasionally behave in twee and precious ways. Polley admits, "I wanted at the outset to feel like we were entering into an almost cliché rom-com." When she watches Waltz with an audience now, "I'm almost cringing for the first 25 minutes. I don't completely begrudge anyone for not liking the way it begins—I hope that people get by the end that I'm not that dumb."

There's some excellent acting all the way through: Williams is far more believable than in the overly mopey Blue Valentine, which looks fairly unambitious in comparison to Waltz. Rogen, without any set-piece-style jokes to hang his shtick on, simply plays a lovable schlub. "I identify more with Lou than any character in the film," Polley says, though her distaste for Margot "melted away a little bit" during the process of making the movie, which was more of a "morality tale" while she was writing it. While Polley allows both sides to state their case, she does ultimately come down with some kind of a judgment: Sarah Silverman's emotionally raw scenes are the damaged soul of Waltz.

The film is loaded with fine, touching moments. The best discussion about relationships happens in the shower of a women's locker room where naked women of all ages and sizes talk about commitment and age and pragmatism. And when things get too interior or whiny, someone always comes along to remind you that this isn't some insipid Hollywood product. When Margot is complaining about how Lou doesn't honor the "courage" it takes for a wife to seduce her husband, he lets loose with an exasperated cry—from always-gentle Rogen, it sounds like a bellow—of "What are you talking about?" She's being ridiculous and he's being obtuse. "They both drive me crazy in that scene," Polley says, because they may as well be speaking two different languages. They drive each other, and us, crazy, too, but this particular blend of love and hate and annoyance is unlike anything you've ever felt for a movie.