There is one instance during Boys and Girls when the film appears to start along an interesting detour, then suddenly backtracks and returns to the well-trodden, expected path. A hint of lesbianism is introduced into the relationship between Jennifer and Amy. From a plot standpoint, it's superfluous, and just leads to a lot of psychological double-speak. In fact, that's one problem with a lot of the dialogue in this movie. The characters don't talk to each other, they talk at each other.
Genuine conversations are scarce.
Aside from a few offhand remarks about papers, homework, and exams, the action here might all be taking place in some young adult fantasy playground. That's in keeping with the film's overall tone, which attempts to divorce itself from reality. For the closing scenes to have a payoff, we need to want these two to be together.