What impressions do you have of Montag and Clarisse's friendship and show how it has made Montag unhappy with his relationship with Mildred?
The friendship is quite brief, remember, and mostly amounts to a few conversations. Montag is grateful, though he never really says so, to Clarisse for opening his eyes to the fantasy life he's been living, and reminding him that it's possible to have something more. Conversely, this knowledge and liberation make it more difficult to continue his unhappy life with his wife, and reveals to him in stark terms for far Millie has faded from reality.
Clarisse is extraordinarily bright and awakens the crital thinking factor in Montag. He has suppressed it all so long that when he meets this girl who questions everything, he enjoys it. Unlike Mildred, Clarisse is alive and interesting. Mildred just sits and watches others on the TV screens...she doesn't live, she lets others' lives roll over her. She conforms to the rules, Clarisse challenges them.
I have not seen the movie version, but I don't think Montag has anything but intrigue and friendship for this girl. In the book, he looks forward to seeing her and even looks for her, but it is for the value of discussion. It is almost as if she is the adult and he is the inquiring child growing into his mind. She is the catalyst in the novel who prompts him to do something about the nagging situation he finds himself in...without her, none of it would have happened.
Clarisse's most important function in the novel is to get Montag to begin to question his role as a fireman and the futuristic society's rules and norms in general. Clarisse is innocent and has not yet been victim to the societal brainwashing. She is a direct contrast to Montag's wife Mildred. Mildred buys whole heartedly into everything she sees on the parlor walls and diligently interacts with the "family", obediently takes her pills, and listens to her seashell radio.
Clarisse buys into none of it, reads, questions, and thinks for herself. She has a sense of history unlike the other people in the society. She is freespirited and freely discusses her feelings and ideas with Montag. This relationship with Clarisse, along with the incident with the woman in the house with the books, prompts Montag to question his entire existence and role in society. Clarisse's death seems to give him another push in leaving his life as a fireman.
In reading the book, I think that Montag's relationship with Clarisse was purely one of friendship. The movie alludes more to a romantic relationship, but if you've seen the movie you'll know that its a lot different than the novel.