Abby
One of the few things that redeemed this movie for me was the character Abby and the apparent total change in story arc when "the Postman" had to rely upon her for survival.
At the point the film apparently stopped revolving around Costner's character and began a seemingly different, but common arc, with Abby (Olivia Williams) taking on a much more dominant role. In the process she goes from being an unfortunate, but somewhat mysteriously callous young woman, to a hard and determined skeptic of "the Postman's" life and motives.
The arc continues to evolve as she takes a firmer and firmer hand in the direction of the story in an attempt to get this questionable character to get up off his lazy butt and do something constructive. Of course she has a motive; she is pregnant and desperately wants a safe place to bear and raise her child.
I would go so far as to say that the chief protagonist switched for about twenty minutes and became Abby's movie not "the Postman's."
I kind of enjoyed this for two reasons. It gave considerably more depth to what otherwise might have been just a minor character. It also showcased Olivia William's talents as an actress.
It kind of astounds me that no one else posting about this movie seems to notice this very important plot twist / element.
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