Video games are just massive sets of rules really. But do you ever find yourself thinking that a certain game should have had some other ones?
I oftentimes find myself making up rules for myself while playing a game, either to get more into the character I'm playing or just to make the game more fun. Like not killing certain types of characters, not using an overpowered weapon, or playing as a drug-addicted psychopath who must consume whatever drugs they come across in Fallout 2 as they find them (more fun that you'd think... in the game.)
Let us know if you've ever made rules for yourself while playing a game.