I think it's mostly about early deficits and needs. The stronger and deeper they are, the more likely transferences are, and the more helpful working them through can be.

I definitely experienced a parental transference with my T, and he also experienced a strong parental counter transference. It wasn't problematic, nor invisible: I became conscious of it very early on, and he worked within a modality that encouraged examination of the transference. Even when our work focussed very cognitively, the transference was a part of that. Being able to work with the transference allowed the past issues with my FOO to be examined with much more clarity and vividness in the moment.

It was the resolving of the transference which allowed me to heal emotionally as well as cognitively. Making the intellectual leaps was easy for me, but didn't change my deepest felt sense of myself--it was the transference that made that possible.

Resolving (by which I mean not just that the feelings faded or magically slipped away or were understood intellectually, but rather were developed fully and experienced completely) the transference is also what makes it possible for both of us to accept the parental connectedness beyond therapy. Because I "grew up" through the transference, and he could support and accept my growth, we can remain connected as Father/adult daughter/friend, and that attachment is very rewarding for both of us.