I work with someone who can be nice or horrible. As can we all. However, while I was warned he tends to bark at people, I was not warned that he can be cruel and hateful. That when you get to work you don't know which he will be.
And he can be frightening. He truly can. And you feed off the emotions of others. So when he is at his worst, you tend to make mistakes. And that makes him angry.
I want to find another job. There have been times I have wanted to walk out. But the hours are perfect and I need to work.