Greta Gerwig shines as a privileged drifter struggling to grow up in a film she co-scripted with Noah BaumbachGreta Gerwig, a Californian educated in New York, emerged from that low-budget area of American independent cinema known for its stumbling verbosity as "mumblecore", first making an impression in the 2008 movie Hannah Takes the Stairs as a would-be playwright with a temporary job in Chicago.