What makes Mrs. Bowles become angry with Montag?

Initially, Mrs. Bowles becomes angry with Montag when she says she doesn't like poetry, and he responds by asking her if she's ever read any. Montag tops things off by reading Dover Beach, which causes Mrs. Phelps to cry..... she believes he has proven her point that books make people sad, depressed, and suicidal.

Mrs. Bowles stood up and glared at Montag. "You see? I knew it, that's what I wanted to prove! I knew it would happen! I've always said, poetry and tears, poetry and suicide and crying and awful feelings, poetry and sickness; all that mush! Now I've had it proved to me. You're nasty, Mr. Montag, you're nasty! "