It's certainly okay to express negative emotions. Anger, frustration, sadness, fear, shame... all of these should happen in some sort of way that is not so intense that it gets out of control.

I've never been so angry with my T that I could have even come close to physically harm him. If I ever felt that way, I might express that I feel that way but not I'd never act out on it (and I don't think my T would push me far enough to feel like that either). It's okay to raise your voice and express your anger. But it should be respectful, not personally insult the therapist.

As for other negative emotions, for example sadness, I once felt so desperate that I curled up on the floor. My T wasn't comfortable with that and told me, but it's not like that was the end of the world, I just sat a slight bit differently.

I have never accused my T of intentionally hurting me. Sometimes he messes up and hurts me, but not in a mean, harmful way. Early on I once told him I felt he wouldn't care because I'm paying him, but I don't think so anymore.