Adolescence has been an evolving cultural concept since, arguably, the Industrial Revolution. Back then, people suddenly were able to build real wealth, creating a middle-class lifestyle that meant the young didn't have to be in a big hurry to be worked to death. They could travel a bit, try out different professions, and maybe even kiss/fondle a few people before settling down.
Unfortunately, enough leisure time to find one's identity also doubles as time for self-doubt. The concept of youthful angst was born, leading to the coming-of-age story, in which a young protagonist tries to figure out where he fits into the big picture. The whole point is that the kid takes a journey that helps him find meaning for himself in the corrupt world of his elders, providing a crystallizing revelation from which to launch his own adulthood.
In recent years, it seems like adolescence has evolved (or devolved, depending on your view). Young people no longer figure out their place in the world in their late teens or early 20s. A lot of people shuffle around, bitching about the parent culture well into their late 20s and beyond. Young 'uns might go through any number of false starts until they feel "? through a combination of peer pressure, experience and shame "? ready to become self-actualized beings.
Written and directed by Noah Baumbach ("Margot at the Wedding"), "Greenberg" presents a subtle mutation on the coming-of-age motif in that our titular protagonist (Ben Stiller, "Night at the Museum: Battle of the Smithsonian") has managed to reach the ripe old age of 41 without getting over his dismay with the world and finding his place in it.
Our understanding of Roger Greenberg's world is first filtered through Florence (Greta Gerwig, "The House of the Devil"), who works as his brother Phillip's (Chris Messina, "Julie & Julia") assistant. Her days are spent floating around the sun-drenched spiritual wasteland that is Los Angeles, generally meeting other peoples' needs. At night, she attends hip events, sometimes going home with the hipsters she meets. Like the girl in the song, Florence doesn't know what love is; she only knows when someone wants her.
When Phillip takes the family on vacation, Florence meets Roger, who has come directly from a psychiatric hospital to house-sit for his brother. Inexplicably, she is drawn to Roger, who is the troubled, prickly-pear sort whom pretty girls are invariably drawn to in movies. He is naturally drawn to Florence, but also knows that getting involved with her is going to be a big hassle that will drain his alone time standing around the house making pained expressions out the window.
On top of dealing with a nascent relationship with Florence, Roger also has to deal with the baggage he left behind in L.A. 15 years before. It seems he was in a semi-successful band with Ivan (Rhys Ifans, "Pirate Radio") and Beller (Mark Duplass, "Humpday"). When the group was offered a recording contract, Roger somehow screwed it up with his Larry David-style social skills, and the band fell apart. Roger left town, and the resentments have been festering ever since. There's also his ex-girlfriend, Beth (Jennifer Jason Leigh, "Synecdoche, New York"), and the rest of his former social circle to contend with, all of whom seem to have morphed into middle-aged, child-rearing teetotalers who look at him with a mix of pity and contempt.
Most of the tension in "Greenberg" comes from Roger attempting to avoid engagement with anyone around him and his inability to stop picking at his social irritations and attendant emotional wounds. His painful back-and-forth with Florence, the wincing conversations with Ivan in which they ignore the elephant in the room, and his general manner are all extremely awkward.
The main question is whether or not Roger will actually learn something and take a step forward as a human being. The way this question is handled is the great success: We don't really know. Roger understands he would be happier if he could let the world in, but it's not clear whether he actually has the option to change. He may just be too habitually bitchy to eliminate the negative and accentuate the positive.
In a way, it's a question that applies to almost everyone, especially those under 30. With all the world's distractions, material excesses and paths to personal estrangement, the possibility of achieving the bildungsroman's crystallizing revelation has become remote, maybe nonexistent.