The narrator is amazed by the tree but his parents quietly reflect on it.
Explanation:
The beginning part of the story tells us that the father of the young boy used to tell them stories of the times when they had natural trees instead of artificial trees. So, when they got to the O'Brien's house, the young boy was actually excited about the tree and observed all of its intricate features.
His parents simply looked at the tree and stared at it with smiles on their faces. They also were silent on their way back from the house. These details apparently show that they reflected on the good times when they still had natural trees.
