Perhaps you must be in the thirty something crowd to really appreciate the time and attention to detail it took for this film to convey the period and the attitude of the characters. It is so sullen and casual it reeks probability and reality. This is not an Oliver Stone idealistic 60's where EVERYONE is wearing bell bottoms and tie dye and driving around in red mustangs.
There is a distinctive generation gap between the parents and children in the movie. The father and mother still pay homage to the 50's and cling to to the ideal of raising a home when it is obvious the kids are already grown and moving on. There is a sense of transition and transformation strong for both parties and you feel the pivot turn.
The girls all each savor a little growing up, unique and personal to themselves while the parents become lost in failed expectation and guilt about the loss of a child years earlier.