All movies are manipulative. It’s their job to nudge us toward some sensation we weren’t expecting. But once in a while a film jets right past the boundaries of artfully contrived tearjerking into a kind of blunt hostage taking. Life Itself, written and directed by Dan Fogelman, the master manipulator behind television’s This Is Us, is so perversely jaw-dropping in its attempts to extort feelings out of us that it could almost be a black comedy.