I think that one of the most prevalent themes in all of the chapters of A Visit From the Goon Squad is the idea that you will never be satisfied with life, and have a constant desire to go back to a time when you were happy, or when you were younger, however, there are also drawback to that time period as well. This theme is exemplified by many different characters throughout the book, because none of them are ever really happy where they are in life.
Bennie is one good example of this theme. Bennie is confused, because he no longer had sexual feelings toward women the way he used to, so "at times Bennie didn't... mind its disappearance" but he also acknowledged that he missed the feeling and wondered "[if he wanted] to live in such a world" (22). He tried hard to get these feelings back in order to feel younger, and remember a time at which he thought he was more successful, by starting a gold flake remedy in order to bring back what he thought would make his life more exciting than it was at that point.
Jocelyn also expresses this dilemma, because later in her life, she shows confusion as to what she wishes she could be. At one point in the story "You (Plural)" Jocelyn talked about how the majority of her life was made up of partying, which her mother called her "desultory twenties" but she said that "[She's] praying it's over" which shows one side of her internal struggle (86). Later in the same chapter, she expresses some sentiment about growing old, and what comes with it- "age, ugliness- they had no place. They would never get in from outside" (88). Jocelyn is conflicted with sentimentality of the past mingled with hope of the future, which is a very post modern idea.
This theme that the novel addresses postmodern because the characters are always somewhat happy and unhappy with their lives all at the same time. The quick pace of their lives leads them to constantly reflect on different times in their life, and the quality and worth of the time they lived. By addressing this theme in her book, Jennifer Egan makes the reader think about their lives in this postmodern way as well.