Maybe I should amend that title, because I really mean musical theater (though I do want to make time to see some plays at some point). I've become a theater addict in the last several months. The main reason I love theater is that it's like real life. Actors can make mistakes or forget their lines (hopefully not in a professional Broadway production). Every performance is slightly different and you can't predict every action even if you've seen the show before. A live performance packs so much more emotional punch than watching a film, especially if you're like me and try to get seats as close to the front as possible. When you go to the theater, you have to concentrate and involve yourself where as with a movie, you can just pause the DVD or turn it off. I suppose you can walk out of the theater, but most people don't do that unless the show is horrible. Theater is not meant to be realistic the way the TV and film are and I think that allows audiences to focus more on the acting and story. Pretty scenery, pretty actors, and special effects can disguise bad material on a screen, but not in a theater (at least not as much). A theater show opening is so much more exciting than a film opening, because you know that the show is only going to be playing for a limited duration whereas you can just wait for the movie to come out on DVD (which sucks all the fun out of it for me). Another nice aspect is revivals. Since good plays and musicals are done more than once, you can compare performances and really appreciate different interpretations of the same material. TV and film is frequently a very passive experience for me and I didn't appreciate the craft of acting until I started learning about theater. I've become more attentive to details (maybe that will help my social life).
I'm not trying to bash TV and film. Rather, I'm trying to say that theater should be more important in American culture than it currently is. That being said, I'll try to catch as many good shows as I can!