I think at the end of the day the thing that makes some people enjoy certain games while others didn't enjoy them as much is the people that you actually play the game with. For example, when I played WoW I was in the top raiding guild on my server, quit, and when I got back into it I got into the best PvP guild on the server. Being able to experience high end raid content and high end arena probably made WoW a far more enjoyable experience for me than it would be for a casual who only gets to run 5-man dungeons and battle grounds for pvp, and those experiences for me were based on who I knew on the game.
Same goes for Halo 3. My brother and my best friend come over every Tuesday night and we play split-screen Halo 3 for hours and hours while drinking beer and enjoying each other's company. Perhaps I'm enjoying the overall experience that I get when I play Halo 3 as opposed to the game itself.
