Sitting, I am like that in T too. I wonder if it is because everyone *starts* T from a different place on the old trusting spectrum. I guess most folk have, at some point in their lifetime, been able to trust at least a few others around them. They know what trust is and have experience of some people being trustworthy. I suppose for them, developing trust in the T relationship is simply a matter of getting to know the T and gradually revealing tidbits about themselves as they 'test the waters'.
I never developed trust with anyone. Ever. Learning to trust in therapy - even a tiny bit - takes me eons. For me, taking that leap to reveal anything even close to vulnerable material is like climbing a mountain in itself.
My T raised this issue with me last time I saw her and wants to discuss it next week. She sort of suggested that perhaps I do not feel comfortable with her and might be able to form a closer therapeutic relationship wth someone else. Funny thing is, from my perpsective I feel very comfortable with her (remembering that I'm judging that according to my frame of reference and (in)ability to trust others). I guess what I am viewing as the beginnings of feeling able to trust is experienced by her as still being given the cold shoulder!

Sorry for the waffle - point being: everyone starts from a different place on the trusting spectrum, and perhaps progress is largely determined by that starting point. Starting on the low end doesn't mean you'll never 'get there', but it may mean it could take a bit longer.