Happiness and compliance
The society Bradbury describes is characterized by very strong capitalism. The "happiness" of the citizens is mainly of a material nature: strong consumption is what people desire. People distract themselves from reality (that a war is threatening, for example) through wild parties and lots of alcohol (Mildred thinks she is just hungover when she wakes up the morning after her suicide attempt). People are "well-fed" and enjoy themselves all the time (p. 89), for which there are amusement parks where young people spend all their time (Part 2, 8%). Families live in houses and have fast cars. Banks are open around the clock.
The billboards are seventy meters high (p. 23), and even when riding the subway you don't have a quiet minute because loud advertisements are playing from the loudspeakers all the time.
Even religion is used for marketing purposes: "Christ is one of the 'family' now.(...) He's a regular peppermint stick now,(...) when he isn't making veiled references to certain commercial products that every worshiper absolutely needs." (Part 2, 26%), says the former literature professor Faber, who conspires with Guy Montag against the system.
Not quite happy
Guy changes in the course of the story. In the beginning, he behaves according to the system and enjoys his job as a fireman. His new neighbor, seventeen-year-old Clarisse, has seeded doubt in his soul by simply asking Guy if he was happy during a conversation on the street...