FZ: "The designers of the multiplayer game City of Heroes thought it would be a wizard wheeze to let users design their own scenarios.
However while some got into the spirit of the thing and invented some quite imaginative ideas, most designed adventures that basically gave their characters shedloads of gear and cash.
It turns out that players quickly found the way to min-max the system, and started making quests that gave huge rewards for little effort. These have blighted the game by becoming the most popular missions and the "developer's favorite" quests are getting poor ratings because they are too hard."