I second this. I had a poor T who raised several red flags in our first few sessions. I have major trust issues, so I decided to give the situation more time in case I was being too sensitive. I ended up being retraumatized by someone who had neither the professional skills nor the personal substance to deal with my issues. I now know to steer clear of therapists who can't make it through the initial phase of therapy without major faux pas.

I also place great emphasis on how the therapist responds to feedback and/or criticism. A T who frequently gets pissy and defensive is ill-suited for the emotionally charged work of therapy.