I think there's a point at which therapy needs to move on from the anger/bitterness, but some therapists really fuel it (at least, the ones I have seen) and it becomes self-destructive. I had one that desperately wanted me to be angry and it did not end well. The one I see now said she thought anger could be healthy, but I think she now sees my point. I let resentment pop up, then fade away. I do not want to live in it.