AvataRPG: The Last Dicebender 004
"Few people grasp the complicated nature of keeping a game entertaining. Take, for example, the event-to-loot exchange rate. If players get too much loot, they stop caring about it and have no incentive to care about the story. If the players get too little loot, they become obsessed with it and completely ignore the story. Only by keeping the exchange rate carefully balanced can a GM keep their players in line. It's still a lot easier, though, than just making the game fun all the time."