After Beatty's visit, Montag is pretty disturbed. Beatty has just revealed to him the entire history of how books came to be so dangerous and unwanted in their society, and it has shaken Montag to the core. The first thing he mentions to his wife after the visit is that he is thinking of quitting his job. He says it would be so easy to just not go in to work tomorrow, or the next day, or the next day. So, obviously Beatty's little history lesson has instilled in him a distaste for the "art" of burning books. He dislikes the idea so much in fact that he doesn't want to ever do it again.
The second response that Montag has is that he wants to "smash things and kill things." This is an interesting response, and goes to show just how upsetting Beatty's visit has been. He is filled with turmoil, confusion and frustration, and wants to vent it somehow. He continues, saying that he is unhappy, angry, heavy; he thinks that books might be the answer, and confesses his hoarding of books to Millie. Then he forces her to read some.
The bottom line is that Beatty's visit solidifies the restlessness and discontent that Montag has been feeling all along. It confirms his unhappiness and pushes him to seek answers. I hope that helped; good luck!