According to pages 3-4, what does Montag think of his job in Fahrenheit 451?
Montag is definitely enamored of his job, but it's a mindless love. The way he is described in the narrative, and the way he describes himself to Clarisse a few pages later, indicates that Montag very much accepts the status quo in society, his life, and the presumed agreement between the two. After all, he does one of the essential jobs in this society, one which is well known and highly regarded (albeit feared) and he has no reason not to enjoy his status, both for the visceral pleasure it brings and for the service that it renders to everyone.
We can also infer that Montag doesn't think at all of the human element of his job; he sees it in an almost poetic sense, and he focuses entirely upon the objects that are being destroyed, not the people or the emotions they may attach to the burning. This is supported in greater detail later, where Montag seems to almost be making excuses as to why he doesn't have to acknowledge that people own these books and attach meaning to them. For him, his job exists in a sort of encapsulated time and place, as though he simply appears, burns an inanimate object, and leaves as cleanly as he came.
Montag loves his job! The first words of the chapter say that it was a "pleasure to burn." He loved to see things "eaten" and to see things "blackened and changed." He sees himself as an artist, as a conductor, who uses his brass nozzle to spray kerosene and play all the amazing "symphonies of blazing and burning." His eyes are all "orange flame" as he anticipates lighting the fire. He wants to shove marshmallows on a stick and roast them in the fire as the books burned. This is a pleasurable experience. Even as he falls asleep at night, he feels the "fiery smile" still gripped by his face muscles. That smile never went away.