What are the two major themes in "O Pioneers"?

In part 2 of O Pioneers we learn that Mrs. Lee won't use the new bathtub because she doesn't want to let go of her old ways.  The themes addressed in this refusal are of the individual against society.  Mrs. Lee is an individual who does not want to exchange her old ways for new ways. Mrs. Lee goes into the tub room and just splashes the water around, then goes to her room at bed time and bathes from a tub under her bed.  Mrs. Lee's actions also address the theme of the human life cycle.  Mrs. Lee is not moving ahead like the younger people in the novel.  This is very typical of elderly people.  They struggle with the new concepts and inventions of society