Pretty much all games are based on black box design, which means player strive to optimize the output of the system. The better the player is at predicting and using the rules that are in the black box, the better they are at the game. This means that most games implicitly task the player to unravel the systems that support them, thus breaking the spell of presence.
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There is a solution to this problem though: keep things simple, let the player fill in the blanks for themselves and make the systems seem more complex then what they really are. Our brains come to the rescue as we are very apt at doing this. The mind constantly needs to take incomplete data and make a big coherent picture of it.

Thomas Grip, The Self, Presence and Story-telling (via notgames)