This is a very interesting thread with great suggestions already. IMO, perfect client (or perfect anything) does not exist but we can still aim to excel in whatever endeavor we engage in and have high standards for quality. I also think that the "perfect" client may mean many different things to different Ts, just like any other preferences people can have in life. I definitely wasn't anywhere near a perfect client, or even a good client, in my own judgment. I did not use therapy for it's primary purposes and then I quit with both Ts after less than a year each. I know I was an interesting person for them and a stimulating interaction partner, but not a client who would actually let them help me in any substantial way.

When I imagine being a therapist and what an appealing client would be for me and rewarding work: people who are able and willing to really be themselves (whether it makes me feel good or not) and people who actually use me and what I can provide as a professional. I would not mind negative transference or other negative reactions if I could figure out with the client what to do with them, how to use them for some purpose. I would like clients who challenge me, expose me to new things and make me try new approaches that would not occur to me otherwise. The main thing that would be hard for me, as I imagine, is clients who remain stuck for very long periods of time and would not show much interest in change - I think this would be hard because I would feel useless in that situation as a professional. I would not want to be the kind of T who just sits there and listens during a long string of sessions - there are many who work that way, I know I would not find it rewarding for me and would not have the patience. Someone introspective and collaborative, who expresses all sorts of thoughts, emotions and brings a great deal of curiosity and desire for improvement, would probably be the most interesting for me. I would definitely welcome a client who interacts and approaches therapy in ways that are less familiar to me, whether it is pleasant or unpleasant to me.

Interesting for me to read (in general on PC) that many people have a deep-seated tendency to act as good girls/boys as some sort of mask, to fit in and be accepted, and hide very significant emotions behind it. That's something I don't relate to much - for me, I have actually had to learn as an adult to be less outspoken and blunt over time and to consciously be a nicer, more accepting person. I do agree with others that these trends stem from childhood. In mine, there wasn't much significant judgment and direction and I was rarely told not to say what was on my mind, and often when I was told I just ignored and went to mind my business. My father was very open and outspoken (at at times a bit insensitive, mostly to others, rarely to me) in a similar way, so there weren't many limits of communication with him - it was very free and natural. My mom was very reserved and suppressed, including that she was suppressed and dominated by both of us (dad and me) most of the time. So when I grew a bit older, I realized that not everyone is like my father or me and I cannot communicate in that way with most people if I want to develop good social skills and be effective in reaching my goals.

I also tend to have high quality standards (not unreasonably high, I think) because I value anything done well and in uniquely creative ways. I try to align myself with those values and stand up to them and it is never easy(!!!) when I fall short. It happens regularly as I have been quite a high achiever in my whole life, but I don't want to give up and compromise below a certain level. I'm still learning how to cut myself a slack.

For me, my high quality standards are not so much relational... I can settle much more easily into being a less perfect or satisfying partner, mate, friend. For me, it is mostly related to my work/professional performance and relating to the objective value of what I produce (e.g. in science or as a piece of art). I can get sloppy, repetitive, inconsistent, hostile and whatnot in therapy and in personal relationships much more easily and with much less anxiety.

Now in retrospect, I think my relative lack of success with therapy was because I did not search enough to find the Ts that would be right for me. The first one was a superficial, overly emotional and reactive, dogmatic person. The second was someone who apparently loves to work with high achievers like me, but seemed to lack the discipline and no-nonsense, no-BS approach that I usually benefit from the most. None of them were very good matches with me, I believe, let alone perfect. I also don't think I shoot for the impossible because I had experienced before in my life quite a few times what it is like to collaborate with and inspired by someone who is a really good fit.

I don't think it is about perfection, or aiming for perfection. I think it is more about interpersonal compatibility - something that, in my good experiences (not with Ts so far) can serve as a very powerful catalyst and drive to progress.