How is the idea that "the best days are the first to pass" shown in "My Antonia"?
First, I am going to sum up this theme in a shorter version - the best hours are the first to pass - as shown in Chapter 9 of the novel. It is in this chapter that the first snowfall happens, and Jim rides over to Antonia's house to take her and Yulka (her sister) on a sleigh ride. The children have wonderful fun for the first part of the day, and are happy and energetic about the cold weather and the snow. However, by the end of the day, they are cold and wet, and Jim ends up getting very sick after returning home. So what seemed wonderful turned out to pass away into complication and trouble.
This is the life of the Bohemian family in this story. The best days are their first days, when they arrive and begin to view the potential of the land purchase they have made. Although the future disappointments are forshadowed in Mrs. Shimerda's disappointment with the sod house, the family is welcomed by their neighbors and are happy. Antonia forms a good and lasting friendship with Jim and the early chapters are dominated much more with hope and energy than with conflict.
However, as time passes, the poor conditions they encountered when arriving have only gotten worse. They are unable to work the land they have bought, and suffer from poverty and hunger. It is this that leads Mr. Shimerda to commit suicide, putting an end to the "best days" and bringing much hard work and sorrow for the family.