This is kind of an intellectual thought or line of thought, but I wanted to run it by folks:
I think that N tendencies are born out of black and white thinking of a certain kind. I have been thinking back on my childhood, and watching my parents, who some of you know are with me during the days now to help with childcare. My parents and I are forging a better relationship, not perfect, but better. They have very N coping mechanisms that get in the way of their further growth and that get in the way of our relationship, and that in general make it tough for things to function smoothly, much to my (and I think their, unconscious) frustration. It has been very helpful for me to try to understand what these barriers are, to make things better now and just to help me keep some perspective when things get weird (as they sometimes do).
The things that stand in the way of smooth functioning, for them, and for the N's I have dated, all center around black and white thinking about themselves and others' perceptions of them. They have to be all the way the best, all the way right, all the way in control, and all the way praised, or it feels to them as if the world has utterly collapsed on them-- they have all of this or none of it. It is so stressful to be contradicted or told what to do or given a task that is driven by someone else's needs that it is almost overwhelming because it suggests that they are terrible, invisible, always wrong, horribly flawed, etc. I can see how uncomfortable it is for them, how devastating, and I can watch them cope by engaging in these N behaviors (not telling the full truth, bragging inappropriately, making really big declarations without any factual basis, going against my wishes in ways that seem capricious and unnecessary, contradicting what I say when there is absolutely no real reason to do so). I have learned to make things work better by trying not to threaten them in the ways that send them over the edge, but of course it's impossible to do this completely, and so the relationship sometimes seems like a car with one flat tire-- there is always this bumpy aspect to it, even when we are moving forward.
I know that analyzing where N tendencies come from isn't that interesting to those of us in relationships with truly psychopathic NPD types-- I have dated men like that and I agree it's better just to run away from them and who cares why they are the way they are. But those of us with Narcissistic Family upbringings might benefit from the analysis because I believe if you grow up this way you have to unlearn the black and white thinking yourself. For the longest time I was super-needy with men because I thought if they didn't love everything about me and if they didn't want to be with me 24-7 then they didn't want me at all. (What a prize I was-- jeez louise). Etc. I think that the seeds of this kind of thinking must be in me even now and I'm going to try to address it in myself as much as possible. The alternative is staying stuck in this infantile black-white world. At the least, for me, identifying the source of the disfunction helps me feel a little less waylayed by it. And I can really specifically make a goal for myself that, even when really stressed, I will try not to fall into those same kinds of thought patterns because I see where it leads.