I like previews and trailers before the movie... sometimes it's informative (new movie that I didn't know about). But really, for me, they act as a palate clean

I like previews and trailers before the movie... sometimes it's informative (new movie that I didn't know about). But really, for me, they act as a palate cleanser of sorts. It sets the stage that I'm about to watch a movie. It serves to separate the "before movie" time from the "movie time". They let my mind shutdown the outside world. But showing documentary footage that spoils the movie I'm about to watch? Yeah... don't do that.