Montag at the beginning of the novel claims that he was happy. He loved his job and was fond of everything about it. He admired the smell of kerosene, kerosene was "nothing but perfume"(6) to Montag. Even his wife, Mildred, disliked the odor but he found it intoxicating. Even if he was happy with his job, he was not happy with his life. He did not realize this until after his conversation with Clarisse. To make matters worse, his wife almost overdosed on sleeping pills when he arrive home that night. He did call for help which sent operators to clean her blood and pump her stomach which confuses him greatly. He sees that the world is not joyful and that everything is not okay. He has just been plastering a smile on his face the whole time.
Montag now fully realizes that he's not happy and needs to change his life. This is starting to affect his work and make him more sluggish. When he arrives at work, he tries to interact with the Hound but it almost attacks him and attempts to kill him. He flees and joins the other fireman upstairs. Montag says "It doesn't like me"(26) to Beatty after what happens. Beatty mocks him, "It doesn't like or dislike"(26) he says, seems to find amusement in it. This causes Montag to suspend Beatty is behind something. Then Montag and the rest of the firemen are called to burn books at a house. They go to the house, check the house, then spread their kerosene but the owner refuses to leave her books. She takes out a match and lets the kerosene, committing suicide. This affects him greatly, makes him more curious about books and if they're really worth dying for.
Montag takes a book with him after leaving the dead woman's house. He calls in sick then next day, too afraid and guilty to go to work. Mildred is of no help until Beatty comes to their house, to check on Montag. While he's there, Beatty explains why books aren't allow. "You must understand that our civilization is so vast that we can't have our minorities upset and stirred"(59) he explains. While the two talks, Mildred tries to fluff Montag's pillow and feels the book underneath his pillow. After Beatty leaves, Montag reveals that he has been taking and hiding books for years now. Mildred is shocked and upset by the confession but Montag tells her that he needs to read them. Montag has changed from a fireman who doesn't care about books, actually loves to burn them to a man who's all about books and wants them to live on.
In Ray Bradbury's novel, Fahrenheit 451, his protagonist Guy Montag goes through several dynamic changes and conflicts. Montag realizes that his life isn't as joyful as he thought to be and wants to change it. He tries to find answers around him and finds out what he's yearning for is books. He goes against himself and his job and takes a book. But eventually, he is caught and makes him take extreme measures. Montag wasn't happy as a fireman, he wanted to learn. He wanted to read books, not burn them.