The quote from John Irving's "Avenue of Mysteries" reflects on the challenges of relationships with certain intense individuals, such as lion tamers. It suggests that the nature of their profession, which requires a significant amount of courage and assertiveness, may translate into traits that could complicate personal interactions. The mention of "testosterone" implies a connection to dominance and aggression, hinting at the underlying complexities in their character.

This observation raises questions about the balance between passion for one's craft and the impact it has on personal life. It speaks to a broader theme of how our vocations can shape our personalities, potentially making some people difficult to live with or understand. Ultimately, it captures the duality of admiration and caution that can exist when engaging with those who lead daring or unconventional lives.