It's nice to do a favor for people.
Trevor is out of food, and he's too busy to go to the store, so he asks Lee.
Lee wants to decide to help Trevor or not.
Lee agrees to help out Trevor, and he goes to the store for him and brings him the groceries.
Lee doesn't help Trevor and goes back to watching football.
Trevor pays Lee for the groceries and thanks him for helping him.
Trevor has to go without food another day this week.