Some people's types are obvious. You meet them and you're instantly like, "That's a slam dunk SEI" (or whatever the case might be). Some people's types aren't immediately obvious, but after observing them and considering various options, their type becomes reasonably clear. Some people, however, seem to have contradictory traits that obscure their type. You might be able to determine that they value this or that or that they're sensory or ethical (or whatever the case might be), but it's still extremely difficult to narrow their type down to one thing.
I believe that with these difficult-to-impossible-to-type-with-confidence people, the issue is generally that they're not acting primarily out of their ego block. For anyone who hasn't read Rick's article about awakening the ego, I strongly encourage you to do so. The basic idea is that different people/types expect different things out of you, and you're likely to alter your behavior in order to get along with or interact with them. The only type who needs you to be EXACTLY who you are is your dual. If you don't spent time around your dual, then chances are good that you'll develop behavior patterns that are atypical of "dualized" people of your type.
The reason I'm saying all of this is because I believe I'm one of those people. I had a large degree of confidence in my LIE typing for years, but at the same time I was mildly depressed and identified more with the negative aspects of my understanding of the typing than the positive aspects. I also attributed things to an understanding of temperaments that was most likely inaccurate. (There are other explanations for my proactive nature.) I knew I was a logical type (because I'm very comfortable with Te/Ti and totally miss or mess up Fi/Fe) and that I value Se, but the other aspects of my typing were based largely on the assumption that symptoms of depression were weak Se and Si.
Back in August I met a "slam dunk" IEI. We gradually became friends and are now pretty close. I questioned my type at the time because it didn't feel like we had an asymmetrical intertype relation. I valued his input as much as he valued mine. I was also finding that when my Se was needed and encouraged, it seemed a hell of a lot stronger than I had previously considered it. I decided at the time that it was probably just that hanging out with your supervisee makes you feel like your 6th function is stronger than it actually is, and that areas of compatibility not related to Socionics were most likely responsible for how well this IEI were getting along.
The more I interacted with him, however (which wasn't really all that much until January or so), the more clear it became that being around him was bringing out sides of me that had been subdued for a very long time. Or perhaps always. (See these two posts for brief descriptions of some of what I was experiencing: http://www.the16types.info/vbulletin/612354-post10.html and http://www.the16types.info/vbulletin/612358-post12.html) I found that my IEI friend was very in need of (and very appreciative of) my input on practical matters, scientific topics, and "Se things". (I'll describe what I mean by "Se things" later.) It was great to have someone need and appreciate that kind of input from me. And the more I offered it, the happier and healthier I felt. At the same time, however, I was finding that when I tried to act the same way at home, my input was criticized. I was also being criticized more at home for being impulsive, insensitive, rude, and immoral (because I gave more consideration to the practical aspects of various situations, such as dealing with problems with my son, than the subjective ethical/moral perspective).
I also found that I needed and appreciated his input as much as he needed and appreciated mine. He always seemed to say exactly the right thing, and he often offered a perspective on something that I would have never come up with on my own, a perspective that really helped clarify things or made me realize important aspects of a situation that I had entirely overlooked. It was always very refreshing being around him. While I was used to spending most of my time around people who were very stern, academic, and critical, being around him was very enjoyable and freeing. I had been having a lot of trouble managing stress, but being around him seemed to diffuse the stress and allowed me to be more productive.
Basically, when I'm at my best, I'm SeTi. The things that I love it when other people appreciate in me are Se and Ti. The things I need are Ni (though I'm still working out exactly what Ni is and how it manifests, tbh) and Fe (this one is MUCH more clear). I realize that all of this is subjective, but this whole "awakening the ego" thing makes perfect sense. I have no reasonable doubt that I might be any other type.
Of course, it all makes perfect sense when I break it down in Model A, too... (additional posts to follow)