Why does Clarisse ask Montag why he is laughing?

During Montag and Clarisse's first conversation, she tells him that she had heard that long ago firemen used to put out fires instead of starting them. Montag's initial reaction is to laugh at Clarisse's comment, and she asks him why he is laughing. Clarisse tells Montag,

You laugh when I haven't been funny and you answer right off. You never stop to think what I've asked you (Bradbury, 3).

Clarisse's response is significant because it...

During Montag and Clarisse's first conversation, she tells him that she had heard that long ago firemen used to put out fires instead of starting them. Montag's initial reaction is to laugh at Clarisse's comment, and she asks him why he is laughing. Clarisse tells Montag,

You laugh when I haven't been funny and you answer right off. You never stop to think what I've asked you (Bradbury, 3).

Clarisse's response is significant because it reveals Montag's nature. Similar to the rest of the citizens in Bradbury's dystopian society, Montag fails to closely analyze the world around him and fails to think critically about questions he is presented. Clarisse notices that Montag's automatic response is to laugh instead of thinking about an acceptable response. In contrast, Clarisse is an insightful, curious teenager, who observes and critiques society. Clarisse's introspective nature affects Montag; he begins to examine his life for the first time. Later on, Clarisse asks Montag if he is happy, and he discovers that he is not. Her minor observations, such as Montag's forced, automatic laugh, make Montag question his life.