Chris Millward wrote in the Lost season 4 episode four discussion:
What are others thoughts on watching previews vs. not?
There have been many cases where the preview goes so far beyond what was necessary to make me interested in a movie/show that I regret having watched it. I still watch previews/trailers for movies (though trepidly), but for serials such as Lost, House, Heroes, etc. I already know I'm going to watch the show. I'd rather not be thinking while watching the show, well I know that Jack is going to be standing there doing ____, and I know that at some point he will be ____, and the show only has 10 minutes left, how are they going to make that happen. There are times when exploiting foreknowledge can end up bettering the experience, but that seems rare with marketing-driven previews. For the most part, I'd rather take in the narrative in a single serving.
An example of being in love with a premise and then having too much revealed in the trailer: Children of Men. The setup, a future with no children, was amazing. For me personally, I wish they hadn't revealed in the trailer that there was a single pregnant woman. There was plenty of opportunity to build tension in the trailer (his relationship with the rebel leader, Orwellian government, a mission of great importance) without the reveal.
Anyway, its a two way street, because I definitely see the benefit to trailers. I just wish there was some way to spark interest without giving away the farm (or a significant piece of the farm).
Open question: Any instances come to mind where previews either enhanced/detracted from the viewing experience?
[I can certainly think of times when previews have done both. For the most part I do not care what happens in the story I want to see how it is told, so I do not care about spoilers. Often I need a spoiler to get me interested -- I did not start watching LOST for example until I heard about that hatch. But now with LOST I would never want anything spoiled by someone who had seen farther ahead than me -- I would not want someone to tell me about a twist. But also, with LOST, I want to be invested in it on a week to week basis. I think guessing at things is part of the experience, as is being ramped up by previews of next week's episode. On the other hand the previews really bothered me when I saw season 3 episode 6 because they called it the "fall finale" and really, it was just an episode, and I felt let down. So I am in a total muddle about this, and, like Chris would like to hear what people think.]