The opening description of book burning is ironic. The first words: "It was a pleasure to burn," are a twist since you are reading a book - the very item that the narrator states it is a pleasure to burn. Bradbury sets up the irony immediately so that what follows reveals the story through dialogue and description rather than a narrator explaining the situation to the reader. One of Clarisse's first questions of Montag in the opening pages is to ask if houses have always been fireproof and have firemen always started, rather than put out, fires. Since that is the opposite of our world, there is irony, especially since Montag says that houses have always been fireproof and firemen have always started fires. Mildred's attempt at killing herself, whether intentional or accidental, is ironic in a society where life is supposed to be all about having a good time and being happy. That point is emphasized when Mildred has no recollection of the event and denies that it happened. The conversations that Montag has with Clarisse are filled with irony, too, especially Clarisse's description of their society. She talks about how fast people move and how little regard there is for life. She talks about how she is considered odd because she likes to talk rather than to be entertained by TV or sports or the other things that occupy most people. Her question to him: "Are you happy?" is ironic because, of course, he isn't happy, though he says that he is.