How if affects real life: Buries itself in your subconscious and refuses to leave.
This doesn't need much explanation - it's the one game everyone has played, probably to death, and suffered from uncontrollable showers of Tetris blocks clicking and clacking together while you desperately try to fall asleep. They. Just. Won't. Get. Out. Of. Your. Head.
This phenomenon isn't exclusive to Tetris; any game with repeating tasks or visual stimulus will cause the hallucination after prolonged use. It's commonly known as the "Tetris Effect," and is said to affect your brain on such a level that even amnesiacs who can't remember playing the game will still see falling blocks in their mind's eye. Creepy!