Frances Ha is a Noah Baumbach film without bitterness. This is perhaps unexpected, given the man’s track record. Greenberg is practically an essay on acerbity, while The Squid and the Whale traffics in plenty of divorce-inspired acrimony. That doesn’t mean that his prior work is somehow one-dimensional or excessively pessimistic, far from it. Rather, it makes his newest feature a surprising deviation into joy, if not necessarily optimism. There’s no doubt that this shift comes courtesy of Greta Gerwig, who co-wrote the script and lights up the screen with her performance. It is a collaboration that blends the artistic sensibilities of Baumbach and Gerwig into a new take on the post-college identity crisis. The lack of belligerence, importantly, is not because the protagonist has nothing about which to be bitter. Frances (Gerwig) is 27 years old, living in Brooklyn, and trying to support herself as an apprentice dancer. Her friends all seem to be doing much better than she is, finding good jobs and nice apartments they can afford. They get progressively more irritating, settling down to married life with Goldman Sachs like irritating bit characters in a Woody Allen party scene. Meanwhile Frances herself is taking step after step in the other direction, losing roommates, jobs and places to live. Yet where Ben Stiller’s Greenberg would just get aggravated and darkly comic, Gerwig has a joie de vivre that refuses to let the film sting.