My T has been firm with me at times...and when that didn't work, he resorted to name calling and mean sarcasm.
I confronted him about it during the next sessions, and he admitted why he did what he did. He wanted to shock me to get me to see that I was in danger. I told him his approach didn't work AT ALL.
Even when I've been dissociative during session, he is directive but not scolding or overly demanding. I'm sure he understands that it could lead to retraumatization. But when he is frustrated at me, he sure does find ways to let me know - and not all of the ways are healthy, IMO.
Most importantly, we find a way to work through it...and we learn and grow from it.