This quote from "City of Ashes" by Cassandra Clare reveals a playful dynamic between the characters, highlighting a mix of humor and boundaries in relationships. The notion of a "No Mundanes Allowed" treehouse symbolizes a sanctuary or a special private space where the character can escape from undesired interactions or the mundane aspects of life. The act of retreating whenever annoyed suggests a coping mechanism that allows one to maintain personal space and mental peace. Simon pointing at Jace adds a layer of social interaction, perhaps teasing or lightheartedly acknowledging the other's reactions.

What stands out here is the relatable theme of human behavior concerning personal boundaries and responses to irritation. Often, people develop symbolic or literal "safe spaces" where they can withdraw to regain composure. This touches on broader emotional and psychological concepts such as self-care, emotional regulation, and the importance of respecting others' limits. The quote also emphasizes the lighter side of relationships—it may contain affection hidden beneath annoyance. It paints a vivid picture of camaraderie where poking fun at each other serves as a bonding mechanism.

The playful tone makes the characters feel authentic and close-knit, reinforcing general truths about the dynamics of friendships or sibling-like relationships. It invites readers to think about their own boundaries and how they communicate discomfort or displeasure. Thus, this simple yet evocative line efficiently captures complex interpersonal nuances in an accessible and memorable way.