It took me over 2 years to be able to express my anger in Therapy. My T knew I was scared if I did he would never let me come back, so he always reassuring me he wasn't going anywhere. He would turn on the white noise machine and explain how it blocked out any noise, whatever he could to make me feel safe. One day I was really po'd with him and he knew it, and the more he tried to get me to talk about the more I told him he was making me angry and to please stop. He just sat back in his chair and said "good, go ahead give it to me". So I gave it to him! I felt horrible afterwards but I did feel alot more trusting of him. He was there the next week and he was okay. I can't verbally express my anger very well outside of therapy yet, so I take it out on myself. I did step over the line once with T and he let me know and that was the biggest turning point in therapy for me because I now have 100% trust in him. Now we can finally work on alot my deeper issues (and theres alot) and I can see a pin prick of light at the end of the tunnel. Geez I didn't mean to write a novel, I really just felt like sharing this.
For what its worth, I know how extremely hard it is to express any anger in therapy but once you can, in whatever way is best for you it feels really good.