1
The most addictive video games have no pre-defined ends. This is one of the central features of a MMORPG, but it is also becoming true for many other genres as well. The most addictive video games have no ultimate goal or point at which a player can say "I'm finished. I have completed every quest - there is nothing new to discover". As such, there is never the experience of "Game Over" - a point which signifies the natural end to a game.