What is the main idea of "Charles"?

The main idea that Shirley Jackson examines throughout the short story concerns the construction and formation of a child's identity. Laurie is initially described by his mother as being a "sweet-voiced nursery-school tot," who discretely explores his aggressive impulses at kindergarten and assumes the identity of a boy named Charles when he describes his bad behavior to his parents. Laurie's parents are depicted as naive, lenient, and enabling. While they perceive Lauries as a good-natured, humorous child, they fail to recognize or correct his rude, destructive behavior and contribute to their son's identity issues by believing his tales. Laurie enjoys manipulating and deceiving his parents by referring himself as Charles in order to escape responsibility and begins to showcase his rude behavior at home.
The fact that Laurie seems to dissociate himself from Charles while engaging in aggressive behavior at school is quite alarming and may suggest a serious mental disorder like "multiple personality disorder" or "dissociative personality disorder." However, Jackson's ambiguity prevents the reader from making a definitive observation concerning Laurie's identity issues and readers may simply dismiss his "split" personality as typical childhood hijinks. Laurie also has the ability to make Charles behave properly at school whenever he pleases, which indicates that he is developing his identity and constructing his character. Overall, Shirley Jackson explores the main idea of identity throughout the short story by depicting Laurie's construction of an alternative, rude child named Charles.

The main idea of Shirley Jackson's short story "Charles" is that affection mixed with indulgence can lead to parental blindness to reality.
Throughout the mother's narration, her parental blinders are on her. As early as in the first paragraph, she remarks upon a change in her "sweet-voiced, nursery-school tot," who seems to her to have transformed, as he "forgot to stop at the corner and wave goodbye" to her.
After school, Laurie returns home "the same way." He flings the door open, throws his cap on the floor, and shouts, "Isn't anybody here?" Then, as they eat lunch, the mother acknowledges that Laurie speaks "insolently" to his father. However, neither parent scolds Laurie for his behavior or his disrespectful speech. This parental leniency and blindness to Laurie's speech and actions only encourage the boy to continue to behave as he does. Even when the mother observes later in the narrative that "Laurie did a Charles when he filled his wagon full of mud and pulled it through the kitchen," she does not deduce that there is a real connection between her son and "Charles."