Listening to: Nothing.
I've been playing the poop out of Assassins Creed II lately and I asked myself, "Why do I keep playing this game?" To be more specific, "Why do I find myself completing all these seemingly meaningless side quests like traveling five minutes to synchronize this viewpoint?" Then it all dawned on my like that time a pigeon pooped on my hat when I was at the Santa Cruz Beach Boardwalk a few weeks ago.
I apparently love mundane tasks.
Now, these can't just be any mundane tasks, mind you. It must be a mundane task presented in a way that is somewhat compelling (yes, I understand that "compelling" thus contradicts the term "mundane", but humor me). It's not to just progress the story, but something that matures/betters your character inside the game. It could be in the form of revealing codex pages (i.e. Assassins Creed II) or adding furniture sets to your home to increase its value. Wait... adding furniture sets to your home to increase its value?
I love Animal Crossing and I realize that it's all probably for the same reason. I go around and deliver presents for Tom Nook because I can ultimately achieve one of a few things: get Bells (to pay off that massive debt), get furniture (in hopes of completing my set), get clothes (because dress-up is fun) or just to build the relationship with that character.
It's just to better your character in this world and, apparently, I love doing this.
Now, it's important to also note that the tasks have to provide a sense of accomplishment in its setting. In the world of Animal Crossing, getting something for free is a massive accomplishment. Even if you don't need the piece of furniture, you can sell it at Tom Nook's store and get some money for it. In the world of Assassins Creed II, it's being an assassin.
It all really boils down to the same thing: complete this task that isn't that hard and then feel like a total bad ass. Sending me out to gather intel before storming a palace for a fine assassination is just an epic version of delivering a shirt to Daisy.
However, upon even closer examination, there's more to this "revelation" of mine. These aren't tasks to progress the story, per se. You're given a choice. You can do it or not. You can go knock down couriers if you want or you could spend all day punching street performers in the face. You could go cutting down all the trees in the town or just spend hours fishing.
I believe it's these side missions of utter blandness that really get me going. I mean the main story is nice and all, but that's not really the thing that gets me to dive deeply into the game. I wouldn't say I was ever deeply engaged with Uncharted 2: Among Thieves, even though I enjoyed the heck out of it.
It's the optional content that adds so much to the game, but only if you want to explore it. Perhaps games that make the whole game essentially optional are the ones I waste the most time with.