In the beginning of "A Small, Good Thing," the baker is a cantankerous and brusquely unpleasant fellow. After the accident, when Ann fails to go in Monday morning to pick up the birthday cake ordered for Scott's eighth birthday, the baker begins calling their house leaving curt and indecipherable messages about the cake they failed to pick up, while thinking of course of the time and cost needed to bake it and the loss of profit from having to sell it as a day-old, two-day-old, even three-day-old cake.
After Scott's painful death, Ann has a spark of relization and understands that the unpleasant baker has been calling to give her grief because of the uncollected--and unpaid for--cake. She and Howard go to the bakery in the dead of night, knowing the baker is there because he just phoned, and bang on his door. In response to the baker's rude, curtness, Ann bursts out in anger at the baker's behavior with the horrible truth that Scott is dead. This is what prompts the change in the baker.
He stops what he has been so busy about and invites Ann and Howard in and offers them chairs to sit on. He then brings them fresh, sweet cinnamon rolls to eat, saying that eating something at a time of shock and mourning is a good thing to do. He sits with Ann and Howard while they eat rolls and he tells them how lonely it feels for him to be without children and to work at a mechanical job to feed the children of other people at other people's celebrations. The baker changes because he has a chance to comfort others by exposing his own suffering, and together they watch the dawn of hope for each of them as the newly arising sun glows palely through the window.