Midway through the movie, Mama says "I'm sick, stop the car." When she gets out, she takes over running across a field. Running and running and running. The Julia Roberts character finally catches her and breathlessly asks "Where are you going? There's no place to go."
That kind of summed up the movie for me...what a great analogy for living with the effects of addiction.
The final scene of the movie...Mama has driven everyone from the house, Julia is the last family member left standing. She impulsively grabs the keys to the old truck and goes roaring down the driveway. A few miles down the road she pulls over, walks up to a fence and gazes across a field. Then, still dressed in pajamas, she gets back in the truck and starts the long drive home.