What is Charles's strongest character trait and why?

In Shirley Jackson's short story "Charles," the title character's strongest trait is his audacity. From the Merriam-Webster online dictionary, audacity is defined as: "A confident and daring quality often seen as shocking or rude." 
In this story, a boy named Laurie invents a boy named Charles to explain his behavior at school. His parents are baffled by the stories of Charles, and concerned. They often overlook the behavior that Laurie displays at home that is mirroring that of his alter ego.
While telling his parents that Charles is responsible, Laurie commits many heinous acts at school. Some of his most audacious acts are: hitting the teacher, yelling so loudly he disturbs other classes, bouncing a see-saw off the head of a classmate, causing her to bleed, punching a boy in the stomach, and convincing a classmate to speak an obscene word, then saying it himself.  
While all these acts are being committed, Laurie's mother and father seem oblivious to Laurie's actions. Even when Laurie's father tries to correct his disrespectful behavior, with a stern "See here, young man," the parents think that it is Charles's influence that has made him act this way. 
At home, Laurie has the audacity to insult his father twice, saying "Hi Pop, y'old dust mop," and the joke: "Look up, look down, look at my thumb, gee you're dumb!" He laughs "insanely" after saying this to his father. He also shouts raucously in the house and down the street on his way home. He spilled his sister's milk and walks away while his father is still talking to him. 
All of these behaviors would be considered audacious today for a kindergartener, but in 1948 when it was first published, it would have seemed incredibly audacious. 
https://www.merriam-webster.com/dictionary/audacity