Tibia/YMMV

Epileptic Trees: popular within the fanbase, especially early on the game had loose plot threads everywhere, such as the Ferumbras quest, hints found in some books ingame, the actual quest only added a few years ago.
Fun for Some: Some players choose to stay on the starting island of Rookgard, which is considered to be the best designed area in the game. Some players even reached level 100 on the island, something that required years of grinding in the limited hunting areas.
Goddamned Bats: Extremely common. Giant spiders are often accompanied by tarantulas, Behemoths have cyclopes and dwarves, etc.
Hilarious in Hindsight: During the first years of the game, the developers told a player that it would probably be impossible to reach level 100 because of the huge amount of EXP required. At the moment, a few players have passed level 400, and passing level 200 is already, while still rare, somewhat mundane. Also, the first player who reached 1,000,000,000 experience points (around level 395) caused a glitch on the official website.
Memetic Mutation: This forum thread evolved from a newbie's angry feelings to a boss creature in game and a cult following dedicated to him.
Ruined FOREVER/Broken Base: Many patches enraged players, since they usually disturb the status quo of the class balance