Like, say, giving good advice?
Actually, yes, that was what I was thinking of.
I'm not sure why most rpgs have such dismal GM advice, I think possibly because people just regurgitate what they saw in the last book they looked at without thinking about it much.
GM advice sections often seem to be an afterthought, when in fact they are critical, most rpgs I see have either no useful GM advice at all or advice that is downright counterproductive.
CoC ironically I see as having rather good GM advice, but then the published scenarios follow none of it and create a model of how to play the game that doesn't really work and doesn't much reflect what the core book says.