Creature should never get angry for no reason. Must only get angry if he sees something worth attacking. Get rid of all other desire-sources for anger.
"If you've shown your creature nothing but nice things, he should *never* get angry unless and until you do something which encourages him to be angry, or he sees a creature/player who makes him angry."
"Similarly for other game-important desires: nice, playful, impress."
Some desires should never be acted on in some circumstances: you should never be playful/tired/etc when there is something scarey nearby.
Creatures must go to the water if they are on fire. This might as well be hard-coded.
"If he's trying to do something, and you give him just the right sort of object, he should use it helpfully."
