"Are you gonna let me in?" Florence (Greta Gerwig) mutters to a driver across the lane from her. It's the first thing we see in Noah Baumbach's difficult, rewarding Greenberg, and it's the key to the movie. In The Squid and the Whale, the director's painful comedy about divorcing writers, the first thing we heard was the younger son instructing his brother, "Me and Mom versus you and Dad"-they were playing doubles tennis, turned out, but the principle was the same.
Here, Florence could be talking to Roger Greenberg (a magnetic Ben Stiller), her employer's brother and a total basket case. Roger is a narcissistic mess-everything he says or does is some kind of ethical stand, and so he does nothing. His friends have learned to compromise; to give up their dreams in order to better serve their spouses or their children or just to keep things together, but Greenberg's case of arrested development has kept him at the maturity level of an idealistic 20-something.
The romance between the two of them, then, makes some sense: Florence is a mature 25-year-old and Roger is an immature 41-year-old. What's startling is how mean Roger is to Florence, and how much of his incremental growth into a better person over the course of the R-rated film (swearing, a graphic sex scene, and copious drug use) happens at her expense.
Baumbach's first movie, Kicking and Screaming, was essentially about the characters in this movie, except that it tracked their progress through the end of their 20s. That film can be very hard to watch, because when it ends no one in it has made any progress. What Greenberg has that Kicking and Screaming lacks is Roger's tentative progress. That, at least, is enough to give us hope for a fictional world that Baumbach has taken great pains to make as frequently disappointing and painful as the real one.