This is why videogames are so interesting; they are, in effect, bottled external worlds, into which we can momentarily plug our inner worlds to see what happens. Each game is a little feedback loop, allowing the player both to imprint his actions into a world, to leave his little mark -- even if only in a high score table -- and to absorb, from a simplified sketch with no social or practical consequences, a new way of being, a new way of doing things.Some people are more concerned with leaving their mark, others more with expanding their horizons. Some give more, some take more. The point is that in their essence, videogames encapsulate this dynamic between the two. They are a study in cause and effect; the easier those worlds are to affect, the more useful a response they give, the more the player owns actions and consequences alike, the more satisfying the experience.
via gamasutra.com