Unconditional positive regard seems a necessity for me, too, and something that I have not gotten through to a successful end to therapy.

It seems to me that a therapist could reflect back their (non-judgmental) personal feelings as JunkDNA mentioned -- sadness, etc., without losing an unconditional positive regard for the client/person as a whole.

In my case, I have a mostly compliant, "nice" exterior personality with a split-off negative, angry part. I can keep the angry part "turned off" and learned over the years in therapy to recognize her "energy" but when I have allowed her "on" to speak in therapy, I have not been able to find a therapist who could tolerate her. Unconditional negative regard for part of me then destroys the "alliance", trust, or relationship one way or the other.