OK, here's a great way of illustrating it that just came to me today.

I had been thinking of the really negative intuitions I sometimes get about things, and realized, the reason Ni will be involved in negative thoughts, is that all of my positive perceptions of abstract data is directed outward. Since our egos naturally gravitate to what is pleasing to them, then we will focus our energy on perceiving or deciding according to those functions and orientations we find the biggest positive associations with.
Since [for me] the ego's inner world is primarily one of linear judgment, abstract perception is rejected from that world, and turned outward. When I want to go inward, then, I turn to concrete data, which is otherwise rejected.

So then what abstract perception is left to be perceived from the inside? The negative stuff ignored by the outward abstracting ego. And what concrete stuff is left to be perceived from the outside? Either stuff I don't want to see or deal with, or stuff I can latch onto to try to trap others or get them off my back.

The same with judgment. I find joy in internal logic, while ethical issues come off as very intrusive to the inner world. It's a threat, like I'm afraid it will condemn the logic or try to pull me away from it, or something. (Hence, I then also tend to want to pull down others lofty moral stances!) So then values are delegated to the outer world. (And even then, it's shaky!) If I can fit in with others, and/or they accept me, the there, the ethics/integrity/self-worth issue is taken care of. (Let someone else 'do all the work' in that area!)
But not in the area of logic! Outer world, keep out of that area! If I feel the need to turn outward to prove or support my inner logic, then
I'll call on an external standard or external efficiency.