I've just reached Winter, the third act in The Last of Us ps3 game and all I can think about is going home and playing some more. Of course I wouldn't have even reached this level if I hadn't been playing with Mike - he can go into a room full of infected over and over again, while I'm left shaking after each encounter (literally shaking too much to keep hold of the controller).
It's the same reason I love (but am useless at) zombie games - they simply terrify me too much. I have nightmares about zombies regularly enough, so when I watch The Walking Dead or play zombie games it affects me even more. So why do it? I can't help myself!
I used to watch scary movies because I loved that edge-of-your-seat feeling; I don't watch many scary movies any more but I still love that thrill of (safe) terror. So while my body is present at work, my mind is traversing the infected landscapes in The Last of Us. Oops. Time to live in the present!