Throughout the book Fahrenheit 451, Guy Montag changes from a relatively "typical" fireman who follows the laws of his society into a person who challenges the laws and eventually becomes an "outcast".
In the book Clarisse McClellan, the 17-years old girl, questions Montag about his life now and the life he has always lived. Near the start of the book Clarisse asks Montag "are you happy" (10), a question that makes him admit later on that "he is not happy" (12).
The fact that Montag actually thinks about Clarisse's question later on and starts admitting to himself that he is not happy is a big step for Montag. In fact he shows how he is no longer living as "one" with society which focuses a lot about "happiness". Thereby, Clarisse is the first to encourage Montag on his way to self-awareness.
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