Games that reach out to you.
Firstly it's Morrowind, with it's beautiful sunset/rise effects (especially the sun reflections on the water surface) and it's overall scenery.
And there is of course Freelancer. It gives me a kind of homecoming feeling, when I take my regular trade run with my trusty Humpback, that takes me between the Colorado and Tau-23 systems (I won't say what I trade, cause this isn't the spoiler forum ). After doing 7-8 of these runs and getting use to them, there is nothing like coming "home" to Colorado, cruising past the Battleship Rio Grande and thinking "only one trade lane left" .
Being affected by a game like this doesn't prove that I am insane, it only proves that the game developers really did their job