What has Hitchcock got to do with good writing?

Why was Alfred Hitchcock a great director? Consider his film, PSYCHO. Robert Bloch’s PSYCHO is an inspiration to all writers who aspire to create a lasting thriller. Why? Because he ushers the reader into the story by showing, not telling. Hitchcock does likewise by allowing the viewer to build a much more terrifying vision in their mind than he could put on the screen. The shower scene is a Hitchcock classic. Sure, a movie is mostly showing – after all it is a movie. However, there is a point where one can "show" too much which becomes like "telling" too much. I think the comparison is a good lesson for a writer.