In "The Glass Castle," a significant incident occurs when a woman spots a mountain lion near her home and triggers a police response that results in the animal's death. This event deeply disturbs Jeannette Walls' father, who believes that wildlife has an inherent right to exist and condemns the woman's actions. His intense anger leads him to punch a wall, illustrating his strong feelings about the value of all living beings.

This moment encapsulates the family's complex relationship with nature and their broader values. Jeannette's father feels a sense of injustice regarding the mountain lion's death, emphasizing that wild creatures should not be harmed simply because they are seen as a threat. His perspective encourages a respect for life and a critical view of how society interacts with wildlife, reflecting the broader themes of humanity's responsibility toward nature in the memoir.