If there is a place where players can exploit gaining experience, items, currency or reputation, then that's precisely what players will do, because they always take the path of least resistance. Since MMO content is measured in months, not hours, the content is paradoxically daunting, so any shortcut to the top will become the most popular route, even if it isn't fun. And if a game's path of least resistance isn't fun, it means the game isn't fun. Lazy or inexperienced game developers blame players for "ruining" a game with aberrant behaviour, but these accusations are like dog owners blaming their pets for eating unhealthy scraps.