I am, in a way, the opposite of this. I consciously force myself to give everyone I interact with the benefit of the doubt. This is an effort, as I know I'm prone to be overly judgemental at times, and often based on things that don't really make sense (an offhand comment from another person etc.). However, if once I've gotten to know someone a bit, I reckon they're idiots*, they are then unconsciously and completely 'written off' and are then definitely use-able as pawns.Not to be scary or anything... This is in my nature.
People always start out as pawns. When I start liking something about these individuals, and see them for who they are, I stop seeing them as chess pieces or tools. Most people on here are just pieces to me, but a few who have managed to reach my heart, like Kyuuei, CaptainChick, Bougal, Sanveane, LadyJaye, PinkPiranha, Entropie, Luminous, Beat and a few others; they have earned importance. I value them as individuals, whereas I do not have the emotional energy to place value upon the large gray masses.
Now, I know this is not morally correct. Or, it isn't in from my POV. Do I still do it sometimes? Yes. Urgh.
I identify with the 'two faces' comment, too. I am definitely one person with my inner circle and another person with everyone else. Not a fake person with everyone else, but certainly a much more polite and toned down version of who I am with close friends. People who know me well know that if I despise someone, I'm probably going to be rigidly polite in any interactions with them.
Is this really an NTJ thing only? Do other types never find themselves just disliking another person so much they genuinely dont care what that person thinks or feels? I mean, think of the stupidest, jerkiest jerk you know - do you REALLY care about how they feel?
*I completely concede that I could be wrong in any one of these judgements, but they still happen, for better or for worse