You can’t keep dwelling on the past when you can’t undo it.
-- Brady (Narration) (chapter 1)

Importance: Chapter 1 functions as a type of prelude wherein Brady looks back at the events of the novel after they have occurred. In this prelude, Brady mentions the above advice, which Brady's father and Carl both articulate. This advice constitutes an important thematic concept in the novel: certain actions are irreversible, but one must not dwell on the past. This idea applies to several different narrative elements such as Ben's death.

I knew [Digger] was sore because the DiAngelos bought his grandfather’s farm, tore down the old house, and built a mansion up there on the bluff.
-- Brady (Narration) (chapter 2)

Importance: The main reason that Digger dislikes Mr. DiAngelo is because the DiAngelos purchased land that used to belong to Digger's grandfather, and Mr. DiAngelo no longer allows Digger to spend time on that land. This tension informs Digger's decision...