Which I kind of don't understand. I could play Halo 3 for hours, and even reach too before I wanted a break. but with Halo 4, I occasionally play couple games of MM a week now, and then I dont have fun and get off for a few days.
It's pretty simple, the gameplay is not rewarding, I don't feel like I can really out-shoot or out-play anyone that is decent at the game. The skill ceiling is so low with the heavy auto aim, terrible strafe and other factors that winning or losing isn't important. I just don't care if someone kills me or if I killed them because the gameplay is so shallow and boring. How can I be invested in a game that is so dumbed down that I don't care about combat encounters?
Even with dumb as fuck bloom in Reach, I could out-shoot players, if I got killed I could justify it as being out-shot or random bullshit. Halo 4 is so stupidly easy that if I get killed it's probably because I was weak to begin with or was shot first, and almost nothing else. The skill ceiling is at the floor, so who cares when you die or get a kill.
Even "Pro Gamers" like Pistola, or Ninja killing me wouldn't matter, I don't care to get better in a game with such boring and shallow core mechanics.