What we say and how we say it matters. Torah teaches us that G-d spoke the world into existence. The world was created through words. The rabbis teach us to guard our tongue from lashon hara (evil speech).
Why is it so easy to be negative? Why do we say hurtful things so often? We know, from firsthand experience, that sticks and stones may break our bones, but words do, in fact, also break us, and yet we say them anyhow.
Towards the end of "Dear Life", Alice Munro’s most recent (and, she says, her final) collection of short stories, Munro shares a memory from her childhood.