Language, history and curiosities in games.
No. Games don’t rot. At least the good ones.
Jargon is good. It creates a culture of play and is just more fun than quoting a rulebook.
Some games are exhaustible. They can be played only so many times before the thrill, the fun, or the mystery is gone. This is fine.
Game players overestimate the gratification they can get out of thinking exhaustively about their options for what they’re going to do on their turn.
A good GM is not afraid to look like an idiot.