I think that the unlike tightly controlled experiences like Left 4 Dead, or games that try to manufacture scares like Resident Evil, the reason that Day Z works so well is precisely because it lacks that control, that manufactured experience that most games insist upon having. Day Z is about as open as any game can get: there are no events, no missions, no explicit friends. The only constants are your depleting food and water meters and that any and all zombies that see you will try to kill you. What's most impressive to me are the stories that come out of this. Like how early on in one of my games, I encountered and befriended another player and we traveled together for a while. We were doing well looking out for each other for a while, until we ran out of ammo. That night, we were attacked by zombies and separated in the pitch blackness. I must have run for 20 minutes trying to shake off my pursuers (some of those zombies can be tenacious). By the time I stopped, I had lost my partner and had no idea where I was. Lost and alone, with my sense of security completely demolished, I set up camp and logged off for the night. It may not be the most interesting story, but this happened to me on the first day that I played the game and I have no doubt that with time and my own improvement at the game that even more interesting stories will emerge.