I'm not sure why you think they're dead ends. Religion is often a lifelong thing and can be very beneficial for you and your community. Politics and history are important throughout your life. I hope I don't have to explain that one.

Revolving a good amount of your life around popular culture absolutely does not mean you don't have your own opinions. If everyone had the same opinion about characters on a show, then there wouldn't be much to talk about. Sure, not everyone is going to have their own opinion on if the latest P=NP paper has any legs to stand on, but who cares?

In addition, what's the difference between watching a high quality TV show or movie and reading a fiction book? Sure, the book may be longer and more detailed, but there are plenty of extremely high quality TV shows being produced now.