here. I won't.
I have this love/hate relationship with movie trailers (also called "previews"). I enjoy watching them as they are often better than the movies they are promoting. They are fun and I enjoy analyzing how they try to sell you on a movie (sometimes I think I should have been in advertising).
But, if it's for a movie I want to see, I don't want to watch the trailer. Why? One word: spoilers. Trailers often show way too much giving away plot twists (or hints at plot twists). I hate sitting in a theater watching a movie and thinking "Oh, he's going to betray the hero because the trailer hinted at it" and then being right.
I have the same problem with previews on television and sometimes book blurbs. They give too much away (I always try not to give too much away in my book blurbs).
Once I went to see a movie with my son and a trailer came on for another movie I wanted to see. I put my coat over my head and hummed loudly so I couldn't hear anything. I'll mute the TV and put my hand up so I can't see the screen when an ad for a movie I want to see comes on (lately, the third Hobbit movie and Interstellar). If I'm watching a television show regularly, I never watch the "next episode" previews for the same reason.
I wonder if it's because I'm a writer I see things other people don't and can figure out plot points and twists with less information. Or maybe everyone else has this problem.
But if I don't want to see the movie, or don't care that much about spoilers, I really enjoy trailers.