I just wrote something on why we laugh together and why we spend so much time watching TV. My idea is that it stems from the brain's mechanism to calibrate our social do's and don'ts to those of the group that we live in.
http://adriaanb.blogspot.com/
Living in a group, our social emotions guide us to overcome the prisoner's dilemmas that we encounter. But because there are many kinds and levels of social rules possible, we need to constantly stay in tune with the rules followed by our group.
The brain's way to calibrate our sensitivities with those of our group is to make us enjoy listening to social narratives, while constantly taking into account the reactions of the people surrounding us. It is these vocal reactions like laughing, booing, cheering etc. that get our social behaviour in tune with that of our group by adjusting our attitudes.
Now that we've automated the tribal storyteller into a TV set, we still enjoy the stories but it has become a waste of time because it lacks the vocal reactions of our group. (The canned laughter like in the Seinfeld episodes is only a poor substitute.)
Please look at the blog for a better explanation. I am trying to get some comments on this idea.
http://adriaanb.blogspot.com/
Adriaan