What makes Mrs. Bowles become angry with Montag?

After Montag reads the poem to Millie and her friends, Mr. Phelps cries, and Mrs. Bowles gets mad at Montag for causing trouble. Mrs. Bowles is angry that Montag made Mrs. Phelps cry.

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! "

"Silly words, silly words, silly awful hurting words," said Mrs. Bowles. "Why do people want to hurt people? Not enough hurt in the world, you've got to tease people with stuff like that ! "