I think one reason we like watching TV and going to the mall is that, when we hit a certain age, those things become what we're culturally expected to like.
At a certain point in childhood, it becomes less cool to say your favorite thing to do when you go home from school is draw or build with legos or wrestle with the dog or put on a silly hat and pretend to be Robin Hood. At a certain point, it becomes less cool to be creative in your spare time, less cool to let your imagination entertain you.
Unless, of course, you're the main characters of Step Brothers. And, maybe I'm crazy, but I think that movie was brilliant social commentary, intentional or not.
(Also tangentially relevant here might be Clay Shirky's thoughts on our cognitive surplus and the future of media: we grew up consuming, but the barriers preventing us from producing and sharing are crumbling, so the days of TV as we know it might be over.)
A little off topic with the Clay Shirky there, but I'm glad to have at least tried to spread some Step Brothers love.
My only complaint about that movie is that they didn't show us any Talladega Nights style outtakes during the credits. I suspect they're saving them for the DVD, which, while certainly a good way to sell DVDs, makes me love the movie a little less. It makes me love it a little more again, however, to know that there are some deleted scenes on Funny or Die.