You don't think though that when it comes to certain personality traits - notably external ones/behaviors - that outsiders aren't sometimes able to be more objective than you yourself?
I would agree outsiders can't possibly know the inner workings/thought processes, or even motivations, but I do think an outsider would be in a better position to label whether someone was utilizing Te more than Fe, for example. Or Ne vs. Se. I mean, mbti is just a categorical system, anyway - it's not the end all be all. So I guess I've never been offended when others have pointed out something about me... I'm more like, 'Huh? Really?' Now, I may not agree, but it would be interesting to me, as a lot of it can boil down to differing perceptions. So, with that, we also all have different ideas of what constitutes each particular personality type.
As for myself, I guess I've always tended to default my personality type to what everyone else views me as, because for one I don't particularly care, and for another thing, I tend to believe I am not in a position to be completely objective in terms of assessing my own personality -- *in terms of mbti categories* -- although I would agree with those saying it's ludicrous to think strangers can know you better than you yourself do. I'm not trying to contradict myself, I swear.

I know who I am better than anyone else does, BUT I may not be in the best position to objectively place myself into one of 16 categories.