I cancelled my Netflix subscription because of the auto-playing previews. I'm surprised people put up with them, let alone that they increase engagement. Half the time the previews are auto-generated. They have a few clips of the show along with some generic music. One of the tracks was reused so often that I started to think of it as the Netflix theme.
I don't like them at all but I do most of my Netflixing on my iPhone, where it doesn't happen.
(When I do go to the Netflix site in a web browser I sometimes temporarily use "Mute site" which is a pretty crazy thing for a site for watching movies to make you want to do!)
