I've been also thinking about systems like this, but wouldn't you need constraints and counting?
I mean let's say you modeled human behavior based on basic economic principles, then you'd have constrains/rules like:<p>if money < x, stay home (and you wouldn't meet new people and have an impact)<p>if money < y, walk instead of taking a bus (and you would get only so far, your reach is small)<p>if money < z, have no energy to do new things (your behavior would stay the same)<p>if energy < c, die<p>edit: adjustments