Of all my favorite games, Runescape is the most unreasonable. A popular MMORPG, Runescape rarely takes itself seriously--its players certainly don't, in any case. Out of scores of servers, the one role-playing server usually has a low population of world-hopping runite ore gatherers and not much else. Doing a quest without having the wiki guide open in another tab is unusual, and NPCs frequently acknowledge the inconsistencies of their gamey world.
The real goal of Runescape is leveling up skills and acquiring wealth and items. The economy is completely ridiculous; gold bars are literally cheaper than dirt while the most expensive and prestigious item in the game is a paper party hat. Leveling any of the 26 available skills is tedious in the extreme. The experience required to get to the next level increases exponentially, and achieving level 99 in a skill, the highest glory, takes anywhere from a week to more than a month. Of playing 12 hours a day. Skill training isn't particularly fun, either. I'm a fishing fan myself: click on fish, wait, click on fish again, wait, deposit fish in bank, click on fish, and so on.
All things considered, though, I've probably spent more time in Runescape than almost any other game. Is it some sort of disease? What could make such a game so popular? My train of thought is just getting started, and I expect to have the answer within two days.