I don't think I've ever screamed, although I have sometimes whimpered, squirmed, or - very occasionally - watched through my fingers (weirdly I never did this as a child, only from around the age of sixteen onwards). I think the last time I watched a scene through my fingers was for A Prophet. The protracted murder scene about twenty minutes in with the razor blade. So disturbing. And yet - in context with the film as a whole - I have to concur that the film would be less powerful if they'd made it less horrible, gory, etc.