Marnie is insane. She is hard to know, and harder to accept. She's a repressed cleptomaniac and a totally ammoral smart-ass, and that's why I love her.
The movie long considered to be one of Hitchcock's lesser works is by far one of his most watchable for repeat viewing. It is a guilty pleasure to watch over and over as Sean Connery traps this con-artist and unabashedly stalks her on a trip through the rabbit hole. As he gets closer to the woman he thinks he loves, he finds that he maybe the one who is trapped.
There are a couple great Hitchcock suspense moments in the movie as well. - Pay close attention to the shoe in the bank heist scene. Even after repeat viewing, it is riveting to watch. I imagine that Alfred put a lot of himself into this movie, and that he had fun making the film. He does a fine job twisting perceptions here. I find that even though Marnie is manic and vicious, I root for her every time.