The movie was terrific - until the end. Then the film cut the last scene in the script. In the screenplay, Ruth quickly buys more paint to sniff (her drug of choice) and we leave her in the same alley where we've seen her before, getting high. She stares at the camera and says, "What are you looking at?"
I love this ending and its confrontation of the easy judgment we can make on this unlikely protagonist. Why was it cut? In an exchange of emails, writer and director Alexander Payne assured me that the decision to cut this scene was his alone. He wanted a more open-ended conclusion, a suggestion that Ruth might make it. I still don't like this ending, which seems too much like a compromise in an otherwise gutsy and tough-minded story.
Ending aside, this movie/script has excellent scene design and is a model of efficient film storytelling. As you watch it, pay particular attention to scene transitions and their efficiency. Two examples:
When the Baby Savers end up in the same cell with Ruth, a beginning writer doubtless would write a long scene of their meeting. Here the transition is from a Baby Saver seeing Ruth in agony on the cell floor -- "Honey, are you all right?" -- to money being counted out as she is bailed out. No dialogue of meeting at all!
In the second example, when the daughter wakes up Ruth on her way out of the house late at night, the transition is from Ruth saying "Party?" to her already getting high in the back of the car, partying with the teenagers. A beginner would have followed them out of the house, meeting the others, beginning to party, etc.
What is left out is as important as what you write in the script. Beginning writers put much too much in, not realizing how efficient the narrative form of screenwriting actually is.