Having been on this orb of ours long enough to have played all sorts of systems from Intellivision on down the line to my current PS4 which I barely ever play only one game really sticks out for me. That's not to say that there haven't been plenty of other games that were purely awesome, but for me it's RTCW or Return to Castle Wolfenstein. The multiplayer to be specific. That game was in my opinion pretty frigging amazing on the cooperative level with the variety of skilled classes and objectives that each map presented. Countless hours were spent coming up with attack plans and defensive strategies for each map. It was a glorious waste of my youth.