Today I will write also about intertextuality (I know I'm kinda behind...:)).
INTERTEXTUALITY: "Is a term to describe the visual referencing between films. Quite literally, films 'borrow' from each other, and you may recognise certain camera angles, aspects of mise en scene, snippets of sound or methods of editing on some films that you have seen in others" [http://candimediateacherthriller11.blogspot.com/2010/12/intertextuality.html]
So besically intertextuality is when some director creates something, and others are inspired by this and creating similar one. My opinion is divided, because I really like some scenes like the popular one in "Psycho" under a shower, and maybe seen once more or twice could be fascinating. But when I see the same or very similar scene for a thousanth time, I'm getting bored. Also there will be lack of suspense, because the viewer knows what will happend.
A good idea could be making similar scene with a fake danger, and the audience will no longer know what will be going on. I cannot say how successful it might be, but its better than copying every single aspect from Hitchcock.
In other hand, Hitchcock has done a great job and the number of similar scenes is just a confirmation to my words. His scene is full of tension and the bathroom climate is full of the fear and unknown. Few films that have borrowed the aspect were "What lies beneath" or "The stepfather". They've also done a good job, even through they've fully coppied the scene.