My kneejerk response when confronted by that sort of cheerleading is to pull in the opposite direction. Part of that is just who I am. Were my therapist to talk about my misery, I'd pull in the opposite direction too. I respond better to a balanced presentation.

But a lot of times I also feel that it invalidates the pain I'm feeling now, or how hard it is, or how much I'm struggling. Simply adding to the beginning "I know how much you're hurting/struggling/etc and I'm not minimizing that" before going on to mention the improvement helps me a lot to accept the positive.

And of course, it goes without saying that it helps if a therapist somehow implies that termination is not imminent.