I thought DayZ as a concept was great. Learning to survive in a post-apocalyptic world where any population center--and any resources it contained--was a hive of undead, with firearms in short supply? It was thrilling early on. I enjoyed the fear in spotting another group of survivors maneuvering quietly along the treeline, worrying that they'd discover our camp, hoping they were just passing by. Actually exchanging fire with a rival group was, at the time, quite rare.
Unfortunately over time it became just another pvp shooter. I'm still looking for a survival game that recreates that sense of tension and fear, but I haven't found it yet.