I agree with BryNTP's and Aimahn's comments about how INTPs (and INTJs, sometimes) come across to others and why. Most INTPs seem interested in a lot of different topics and, therefore, learn what they can about them when the opportunities arise. For me, there are so many different topics of interest that I'm quite aware that I've "only scratched the surface" on most of them. This, however, doesn't stop me from forming some opinions on the topic. And, because the topic is of interest and someone says their opinion on the topic, if their opinion doesn't jive with the information I have gathered (as limited as it might be), I will mention this fact and share the information I gathered. I do this because I am aware that I don't know everything about the topic, and I definitely want to know more and more and more. It isn't an attempt to be a know-it-all or to exclude their opinion, it is an attempt to learn more and to possibly refine my opinion, in case the other person has some facts to share that I have yet to discover. However, if the other person is offended by this process, the potentially fun interaction falls apart.
INTJ: uncomfortable with tangents; must think within framework/system they've built and want to talk about that rather than other ways of doing it...at least when they are in the mood to talk only about the system they are building the way they want to build it. Hard to describe, and I know I'm doing a poor job of it.
INTP: most comfortable when ends are left loose and all possible possibilities are thought through and no final commitments are made; tend toward melancholy or existential depression, at times.
ENTJ: comes across repeatedly as "it's my way or the highway."
ENTP: the one I know IRL is quite manipulative with people and tends to be divisive in a group in order to look "best" at something.
