There's nothing silly about what makes you happy.
-- Tom (Chapter 4: Then)

Importance: Tom says this to Elizabeth in reference to her passion for painting. Tom is the first person to take Elizabeth's vocation seriously. He validates her feelings and reassures her that her dedication to her art is not futile but actually admirable. Tom's words inspire Elizabeth and give her the required momentum to persist in her hobby.

Instead they remained forever young, their relationship one of eternal hope.
-- Narrator (Chapter 1: Now)

Importance: This quote perfectly captures the nature of Elizabeth and Tom's relationship. They skipped over all the arguments and trials that come with marriage and instead go on loving each other as they did when they were teenagers. They relish this place of "eternal hope" because it suggests endless possibilities for their future (7). Even when Elizabeth and Tom do reunite, their relationship remains playful and youthful, in keeping with their younger selves.

Tom was the only...
-- Narrator (Chapter 12: Then)