One night in the chatroom, somebody asked what line everybody thought captured the themes of BBM in a nutshell. So we started naming the obvious ones, "If you can't fix it ..." "Ain't no reins ..." and so on. But then people started getting more adventuresome and out there: "No more beans ..." "This is a TIAGDBOAUS," "I think my dad was right" "He's going to be buried in the family plot" -- and we noticed that a lot of those summed up the themes really well, too!
It's like you can almost randomly pick any line in the movie and see a double meaning to it, often one that holds much larger ideas.
Take my username. When Alma Jr. says "Mommy, I need crayons," I think she's expressing a need we all have for crayons in our lives -- that is, for color, beauty, love, happiness, joy. Ennis always denied himself crayons.