And trailers are almost always extremely misleading, and give away some of the biggest spoilers in the film. I tend to steer clear of trailers and the general PR hype surrounding movie releases, these days.
I'm a little confused by the question. Why wouldn't film makers use trailers? At the end of the day even if a film is pants it is there to make money so they will naturally advertise and build hype around it.
Sorry I should have elaborated.
What I was questioning was the obsession and importance which some posters attach to them- indeed I wonder sometimes if they bother to see the film at all.
Ah I see. I haven't seen any real obsession with them. But I think it is only natural if people are fans of a franchise, genre or a character (say like Captain America) that is appearing in a movie that they would get excited by a trailer. It whets the appetite.