I'm trying to find ideas and examples within the novel The Art of Racing in the Rain as to how Denny's response to difficult circumstances shapes who we become in the future. It would be nice to have insight and examples for both Denny and Enzo, if possible.

Garth Stein decided to tell this story from the perspective of Enzo, the dog. Once he became a family pet, Enzo played an important role in helping the humans through difficult times. Denny was first a devoted pet owner and then a devoted family man; he understood that it was important that Eve, his girlfriend and then wife, accepted Enzo as a family member. While no one could have predicted that Eve would become ill and die very young, Enzo’s actions helped Eve through her last days and then helped their daughter, Zoe, and Denny with grief and recovery.
As the novel begins, when Enzo is old and near death, the reader learns right away that he remained a family pet for many years. As he reminisces about the early years he spent with Denny after being adopted, we learn that he made an adjustment from farm life to city life in Seattle. This information establishes his adaptable personality. When Eve entered Denny’s life, Enzo faced another challenge, as Denny’s affections were diverted. Here as well, Enzo proved adaptable, and he and Eve also developed a close relationship. This becomes crucial when Zoe is born and Enzo accepts the responsibility that Eve asks of him: to protect Zoe. As Eve nears death as well, she relies on Enzo’s presence and confides in him. He is so invested in the family that he even dreams he can testify in court when Denny has legal troubles.
Denny’s character is filtered through the eyes of Enzo, who is a devoted pet, so the reader’s impression of him is generally positive. His initial apparently negative traits are those that affected Enzo when he initially saw Eve as a rival; for the reader, Denny’s behavior in loving and marrying this young woman are entirely appropriate. Denny, although he has flaws, evolves from his primary role as a racer (who is away at a race when his daughter is born) to a young family man, with the changes that come with being a father. These include taking a regular retail job and buying a house.
After Eve becomes ill, Denny must make further decisions of this kind. He turns down a job on a race team that would take him away for six months, suspecting that Eve’s illness is terminal and that Zoe needs him. He continues racing, however, and is often gone for several days at a time, but finally, a crash makes him admit that he will not become a racing star. The additional adjustments come after Eve’s brain tumor is diagnosed, and adulthood means putting her needs and their daughter’s needs first, even though this means allowing both of them to live temporarily with Eve’s parents.
The situation grows even more complicated through an incident involving a teenage girl who attempts to seduce Denny and then, after Eve’s death, accuses him of sexual assault. Denny must face legal action and the prospect of losing custody of Zoe to Eve’s parents. Finally, reconciliation with his own parents provides closure and the funds for his legal defense. Although his dream of competitive racing has faded, his passion for cars pays off: he is hired to test-drive Ferraris. After Denny regains custody of Zoe, Enzo finally passes away, and father and daughter move to Italy for his new career.