On 2009-06-16, Mathieu Leocmach wrote:
make sure that your game's rules treat now your character's in action and this is what your character's action is as significant. Especially, make sure that somebody else needs to know that now your character's in action, and needs to know what your character's action is, in order to make her decisions.
I love this explanation. Usually a system description is centered on one player, the one who is acting. You manage to show that the player(s) who will have to react to the action is/are as important in the picture as this now-acting player. They don't only react, they shape the present action resolution.
It may be something evident, but for me it's a real breakthrough.