After I first saw the movie Psycho as an impressionable youth, there wasn’t a week that went by for several years that, while taking a shower, I didn’t recall (and get freaked out by) this great scene:

 INT. MARY IN SHOWER

         Over the bar on which hangs the shower curtain, we can see         the bathroom door, not entirely closed. For a moment we watch         Mary as she washes and soaps herself.

         There is still a small worry in her eyes, but generally she         looks somewhat relieved.

         Now we see the bathroom door being pushed slowly open.

         The noise of the shower drowns out any sound. The door is         then slowly and carefully closed.

         And we see the shadow of a woman fall across the shower         curtain. Mary's back is turned to the curtain. The white         brightness of the bathroom is almost blinding.

         Suddenly we see the hand reach up, grasp the shower curtain,         rip it aside.

                                                              CUT TO:

         MARY - ECU

         As she turns in response to the feel and SOUND of the shower         curtain being torn aside. A look of pure horror erupts in         her face. A low terrible groan begins to rise up out of her         throat. A hand comes into the shot. The hand holds an enormous         bread knife. The flint of the blade shatters the screen to         an almost total, silver blankness.

         THE SLASHING

         An impression of a knife slashing, as if tearing at the very         screen, ripping the film. Over it the brief gulps of         screaming. And then silence. And then the dreadful thump as         Mary's body falls in the tub.

         REVERSE ANGLE

         The blank whiteness, the blur of the shower water, the hand         pulling the shower curtain back. We catch one flicker of a         glimpse of the murderer. A woman, her face contorted with         madness, her head wild with hair, as if she were wearing a         fright-wig.  And then we see only the curtain, closed across         the tub, and hear the rush of the shower water. Above the         shower-bar we see the bathroom door open again and after a         moment we HEAR the SOUND of the front door slamming.

                                                              CUT TO:

         THE DEAD BODY

         Lying half in, half out of the tub, the head tumbled over,         touching the floor, the hair wet, one eye wide open as if         popped, one arm lying limp and wet along the tile floor.         Coming down the side of the tub, running thick and dark along         the porcelain, we see many small threads of blood. CAMERA         FOLLOWS away from the body, travels slowly across the         bathroom, past the toilet, out into the bedroom. As CAMERA         approaches the bed, we see the folded newspaper as Mary placed         it on the bedside table.

         CLOSE UP - THE NEWSPAPER

         beside the bed. The CAMERA now moves away over to the window         and looks up to the house, and as it gets there we HEAR,         coming from within the house, the SOUND of Norman's fearful,         shocked voice.

                               NORMAN'S VOICE                   Mother! Oh God, what... blood,                   blood... mother...!

One of the reasons the scene is so compelling is because of its ‘slashing’ pace — compared to every scene up to this point, which play out at a rather leisurely speed, the shower scene — from the point of attack to Norman’s departure — is (I’ve read) 78 shots in 45 seconds. You can go here to see a shot-by-shot breakdown of the scene. And here is the shower scene in all its bloody glory (Happy Halloween!):

[youtube=http://www.youtube.com/watch?v=zLJ2qv_Wcug]