Hatred. Here's how it worked for me: I attached to T, dumped my hate on her and now it's gone. It took seven years for me to say, "I do not hate you any more," but I probably had more than the usual dose of hate. She said something about me probably hating her again from time to time.

T's expect to be hated. They know it's not forever.

I wouldn't tell him that (I hope) but it probably has helped to tell him how hopeless therapy seems several times. I don't know if it's something he did after I told him it seemed like I've been doing this for 2 years and it's not helping, but he said he'd be more patient, and at the next session he was very supportive. It helped and I felt like there was some progress for a little while.

The hardest part of therapy is learning how to do therapy. That was what my college T told me many years ago. And I hated him at the time. But he was right.
It may not feel like you are making progress, but the very act of going into session with an open heart says a lot about a person.