So many people were so nice to offer their insights about persons #1 & 2. Although I understand some people may have been annoyed at my admission of not being perfectly objective in description #2, I was trying hard and think I gave a good realistic portrait. Nevertheless, both of these people, especially #2, seem to exemplify some of the paradoxes involving ITj vs. ETj.
Anyhow, what I'd really like to see is your reaction to #3. I've tried very hard to be objective here. I know this is kind of a long profile, but I think you'll find it interesting to try to see what type this person might be from this description.
He appears quiet and reserved, and he requires absolute silence and freedom to do his best work. He abhors distractions around him. He can seem lost at social gatherings, but is good company in one-on-one conversation, in which case he seems more outgoing. At times, he may be very open to conversation, but not imposing himself too much. He rarely likes the conversation to be focused on himself. Instead, he wants to know what the other person thinks. Discussion of actions puts him on edge; he's inclined to try to shift the conversation to some topic that doesn't put him on the spot. He likes to ask questions that show off his analytic abilities. He can hardly contain himself in giving suggestions.
Although he can hand in finished work, he seems to never consider it complete...always open to revision. It's as if he's seeking some sort of "ideal" that he has trouble achieving. Moreover, he seems to get some of his best ideas when he's revising something.
He appears a slave to his own mental processes. He'll get caught up in investigating something and let more important and urgent concerns fall by the wayside. Sometimes he mentions his feeling of guilt about not being responsible, but he doesn't change his behavior. Very occasionally, he gets stuff done but looks like a machine or toy soldier in the process. At any rate, he can seem very focused when discussing tasks, even if he's not so great at doing them. He may procrastinate something for a long time; but once he gets it in his head, he'll work on it for a long time without stopping. His lack of attention to things often causes problems for him, and he seems to just accept that as the way life is. He sees what needs to be done, but just doesn't do it. When he does, he looks like he's in a slow-motion film. His biggest excuse is that there just isn't time.
There are days when he's so caught up in investigating something or working on an artistic project that he won't go out at all, or talk to anyone, although he's usually friendly if someone calls. (Sometimes he's abrupt, though, if he's in deep thought.) It seems that if left to his own devices, he might never go out. One strength is that he digs to the core of a problem after others would have given up.
His biggest problem is that he does things slowly; he's wasted in situations that require a lot of busywork, and much better if doing something more creative or artistic. He's really good at solving other people's technical problems, or giving advice...except that he doesn't take his own advice. When doing something that requires detailed work, he's very fastidious about each detail but takes a long time and takes lots of breaks.
He's good at teaching; he seems to know the right thing to say. He's calm, patient, and very diplomatic if he needs to point out if someone needs correction. He seems good at seeing things from another person's point of view. He listens to anybody's idea at all and considers it worthy of consideration, although he gets impatient with small talk or what he sees as boring details. He's very flexible and seems inclined to do what another person wants, and is particularly attentive if he notices someone is feeling bad. He's pretty good at consoling people who are close to him.
He sometimes says things about fields that he probably doesn't know that much about; but what he says is logical, and that's why he can have something to say. His writing can be complex, which makes it seem as if he knows something. Sometimes people question if he really knows what he's talking about because he has his own way of seeing things.
He takes a lot of notes; it seems he always has ideas for new businesses, stories, fanciful nonsense, or just about life. But he never does anything with his ideas, which is very strange. They just pile up.
He can antagonize people without knowing it. Sometimes he makes suggestions or does things that cause other people to be shocked, but he isn't aware unless someone points it out to him, at which point he becomes very apologetic and much more careful. He's always eager to patch up disagreements.