The way you describe every type you mentioned seems backwards to me, but I have a feeling that it might just be because the adjectives you use mean something different to me than they do to you.
I would agree with your first sentence.... but everything after that has me scratching my head.
ISTJs have to be some of the least mysterious and unusual people out there.
Are you sure your friend is a ISTJ?
ISTJs are very mysterious and unusual...they are not mysterious in a childish way, like INFJs are...ISTJs have mysteriousness and originality, but along with will power and maturity. A typical ISTJ male will be the lone wolf, respected by people but rarely understood.
So, I'm not sure your friend is a ISTJ, who dresses "very eccentrically and dabbles in alternative lifestyles". That's very unlikely for ISTJs.
They are rational people, serious, with capability for long-term decision making, with regard to practical matters. They are by no means not given to silly things like wearing eccentric clothes.
or to explain myself better, stuffs like "pop" whatever (music, movies, movements) does not interest the typical ISTJs, and also ESTJs. Its because they can see right trough that. Those are serious people, mature, strong and stoic, traditional.
they are the introverted version of ESTJs...imagine that.
Also ISTJs are very rare, from my experience, much more rare then INFJs (but with respect to this, its just my opinion, against MBTI, who says INFJs are "rare")
But even the most "weird" ones are quirky in a way that's very predictable if you know them. They're still Si doms, creatures of comfort and habit, even if their individual patterns don't conform to the norm. They're the ones I'd describe as "simple," in the sense that they're generally straightforward and easy to figure out.
i don't think any man is "easy to figure out", and least likely a ISTJ.
ENFPs, I wouldn't really describe as simple, but I think we may just have different ideas of what that means. ENFPs tend to find a lot of joy in simple pleasures and can have a childlike sense of excitement. If that's what you mean by simple, then I agree.
no, I mean simple in the sense of a person's influence, strenght of personality, rank in society, potential to influence people, to awe people, to make people fall into their influence and leadership.
But they can also be extremely emotionally convoluted and have severely low self esteem. When in this state, it's nearly impossible to predict what will send them into hysterics, and you have to walk on eggshells around them, but the most innocuous thing can set them off.
I already said that ENFPs, as far as I know in my experience, are not the kind of people who are worried about self-esteem things.
There are several reasons for this:
Firstly, they are from the "Gamma" group in Socionics. This group, who is composed of ESTJs, ISTJs, ENFPs and INFPs, are the most mature types in all typology (like really mature, in the sense that they make decisions like adults and have responsabilities like a adult would have).
Secondly, all the gamma group has a "serious" approach to life...not in the sense that they do not have fun or laugh, but in the more deeper sense, that they advance and learn in life with all seriousness, not just with regard to knowledge, but also with regard to action, and taking the most ethical and beneficial decisions for the human good (that is te coupled with Fi). They are also the most ethical group.
That is because they are traditional people, they stick to rules, and respect authority.
It's the dreaded Fi-Si loop. Something as seemingly ridiculous as saying the word "yellow" can set them off. "I was wearing a yellow shirt the day I got a rejection letter from my top college! Yellow is a reminder of what a failure I am, please never bring it up again!" Okay, that's an extreme example, but you get the point.
The Fi-Si loop causes them to associate (often negative) feelings with the circumstances under which those feelings were felt, even if those contextual details were not the cause of the negative feeling. Emotionally, for Fi/Si users, if there is one sour grape in the bunch, it often ruins the whole bunch.
I think ENFPs are one of the few types who have naturaly a healthy self-esteem. Of coursem there are exceptions, but in general, as a type, ENFPs have a sense of self-esteem, and they advance slowly but surely in life (because they are also bug dreamers, like INFJs are)
One reason ENFPs might be drawn to INFJs is because we are usually more understanding and patient with people than other types. When ENFPs are under stress, they can't help but feel what they're feeling very strongly, even when they know they're being irrational. Rationalizing won't make their emotions go away, and knowing that their hypersensitivity is a nuisance to others just makes them feel worse. So it makes sense that they'd be drawn to natural counselors like INFJs.
I understand and I respect your opinion, but I disagree.
reason being because ENFPs are not in need of counselors, unless they are psychologicaly sick, but that is usualy very rare for ENFPs.
Secondly, a good counselor would have to be himself psychologicaly sane and healthy, and usualy INFJs are not like that, especialy in the Western society, because of the pressure that is being put up on this type. So I don't think INFJs are "counselors", and I also don't think ENFPs seek friendship with INFJs because they need a "natural counselor".
When I said INFJs are not sane and healthy, I meant a great majority of them of course, not all of them.
).
I love reading what other types think of ENFP. 
