Well, the idea is that you could be Socionics ISTj. I still don't know if I'm ISTj. If yes, then guess what, the definitions are screwed up. Supposedly Dick Cheney is ISTj/ISTP. But, you seem to infer that you disagree.
The fact that you are saying mood expressions makes me think that you are. If so, then INFJ. My existence fits the definition. Thus we would be the same.
I am also a functionalist, and have taken to quantifying the functions functionally. I shall explain to you my conception of the functions. I think that Ni is realtable to long trains of thought. Fe is relatable to expression of emotions, which Fi users see through, and don't care about, which is who I believe you've been with. Probably a self proclaimed INFJ. Problem with INFJ and INFP is that they are very similar. For whatever reason, INFPs want to be special. I can say with pride that I don't really give a crap whether you are special or not, I just want to use you to make the world a better place. If I can't, then I'll leave.
I can imagine a long train of thought in that you thought. So, Ni. And you said Mood expressions. Fe. INFJ. Other options include ISTP, ESTP, or ENFJ. Pretty much anyone in this:
Beta Quadra - Wikisocion
Logically these people would be drawn here.
So. Which are you? As a note, seeing that you don't think you are ISTP, I would go with INFJ. I always go with people's self typing except in when I think they understand the definition wrong.
As a note, socionics is a theory that works with communication. For example, I say obly googly ook, and someone out there knows and understands why my garbled weirdness. So by the theory, it should be you. You might disagree with it, but it should seem effortless to understand.
So goes the theory, at least. But yeah. Not giving a crap about the social organization is also a tell for something, but I don't know what.