nPC Nature, interests, & sentiment

I finally read through +Vincent Baker's "Amazons," and it is really fantastic. There is a lot to think and talk about in terms of design, so this may seem a weird thing to focus on, but for some reason it really struck me.

One of the actions available to the World players is to "Have someone act." These are the rules for "choos[ing] someone's action":

When someone's nature, interests, and sentiment align, have her act on them.

Otherwise, you can have her act according to her nature, against her interests and sentiment; or else according to her interests and sentiment, against her nature.

Those two rules for NPC actions are both insightful and powerful. They are one of those things that you know you know and that you recognize as soon as you see it but that you hadn't bothered to hammer into words before. ​