One of my buddies is the most like Greg. He'll swear up and down that a game isn't complicated and then try to teach because he knows all the rules. 45 minutes later I'm sitting there glassy eyed and still haven't even taken the first turn.
When we tried to play Game of Thrones his rules teach included the history of each house represented in the game. Because "We needed to know how they acted so that we could play them correctly". I nearly lost my mind.