Unlike the novel, where Norman is a slightly off-putting, slovenly middle aged man, similar to Ed Gein who inspired his creation, the movie Norman is a handsome boy-next-door type, who you wouldnt suspect of being a psychopath. Sound familiar?
Norman's sudden mood swings can be downright terrifying. Special mention goes to his "We all go a little mad sometimes." line, where he says the line in a desperate and frustrated tone, before immediately switching to his affable and smiling self.
The teaser trailer isn't very remarkable on the surface. Alfred Hitchcock himself gives a tour of the movie set while also semi-spoiling all the twists and scary moments of the film while whimsical music plays in the background. However at the end, Hitchcock goes to the bathroom, where the shower scene was filmed. He decides to peek behind the shower curtain, and we're greeted with a shot of Marion Crane making a blood-curdling scream as the movie title appears and the "Psycho" Strings play. This, in itself, isn't very much considering how famous the movie is today. But imagine being a movie-goer at the theater when this trailer started playing. With the way it was presented up until the very end, you will inevitably get Jump Scare'd.
In a way, the trailer itself. Oh yeah, it seems silly and modest at first, but take a proverbial closer look...first off, we have the calm, comfortable monotone Hitchcock uses to describe all the (literally) gory details of the murders as he gives us a guided tour of the Bates Motel. Second off, we have Nothing Is Scarier invoked to the Nth degree. At one point, he mentions that Mrs. Bates' clothes are still in her closet, looks into said closet and sees...something that we don't see. Whatever he's seeing, be it ugly clothes or a dead body, it seems to disturb him a little. And lastly? The fact that he can talk about all this gory, bloody stuff...and yet, the motivation of the murder is so gruesome that he just can't bring himself to talk about it. It's at that point that you realize that you have to see this movie in order to figure out just what the Master of Suspense is so speechless about!
One of the most disturbing things about that scene was the very sexualized way in which it was handled. The fact that Norman just watched Marion undress, the close-up on her stomach, her heavy breathing right before she died... Does This Remind You of Anything?
As well as the distinctly phallic silhouette of the knife, the ejaculatory spurts of blood. It's classic Hitchcock symbolism.
Janet Leigh, after watching the shower sequence, didn't take another shower for many years after.
It's not watching the shower scene itself that is uncomfortable, it's the seed you have planted your mind the next time you take a shower alone. The whole tiny box / nowhere to run thing doesn't help, either. The noise of the shower and the opaque curtain, allowing just anybody to sneak in, if they're careful enough... it's Nightmare and Paranoia Fuel all in one!
The novel's description of the shower scene is even worse than the movie:
"It was the knife that a moment later cut off her scream...and her head."
Mother: "It's sad when a mother has to speak the words that condemn her own son. But I couldn't allow them to believe that I would commit murder. They'll put him away now as I should have years ago. He was always bad and in the end he intended to tell them I killed those girls and that man, as if I could do anything except just sit and stare like one of his stuffed birds. Oh, they know I can't even move a finger and I won't. I'll just sit here and be quiet just in case they do.... suspect me. They're probably watching me. Well, let them. Let them see what kind of a person I am. I'm not even going to swat that fly. I hope they are watching... they'll see. They'll see and they'll know, and they'll say, 'Why, she wouldn't even harm a fly.'"
This happens in the novel as well, and unlike the film, the sequel doesn't undo it. Norman never gets better, his personality is essentially killed off, and Mother becomes the sole personality until their death after escaping from the asylum decades later.
Not to mention the music. It's a chilling reprise of "The Madhouse" (the music that plays during the parlor scene mentioned below), making an already creepy piece even creepier.
The image of Norman barging into the basement, wearing a wig and his mother's clothes and screaming bloody murder at the top of his lungs while wielding a knife, is also terrifying all on its own.
Arbogast's murder. Especially since that one wasn't subject to Popcultural Osmosis, so you may not even see it coming.
The whole parlorscene is one of the tensest and most nerve-wracking in the film, despite or rather because of the fact that nothing truly nasty ultimately happens. Norman is a pleasant, good-looking young man, but there's just something so off about him, especially when he starts asking very prying questions, making Marion (and the audience) increasingly uncomfortable. And when Marion suggests that maybe he should arrange to move his mother into "someplace...", he gets really intense.
Norman: You know what I think? We're all in our private traps. Clamped in them. And none of us can ever get out. We scratch and... and claw, but... but only at the air. Only at each other. And for all of it, we never budge an inch.
And the accompanying music, a piece of creeping horror that intensifies the already uneasy atmosphere.
Ironically, if you watch the film trying to take on the mindset of someone who doesn't know the ending, it looks just as plausible from that perspective that Marion- who is, after all, an adulteress and a thief on the run herself, with a notably cold manner- might want to rid herself of this earnest, chatty young man to cover her tracks- an impression Hitchcock almost certainly wanted the original viewers to consider. Until the shock of her murder scene, Marion herself is framed as someone who might be on the brink of Jumping Off the Slippery Slope, and a pre-Pop-Cultural Osmosis viewer might have assumed she was the "psycho"!
The highway police officer. Sure he's just doing his job, and the way Marion's acting gives him every right to be suspicious, but he never takes his glasses off, so there are just two black circles where his eyes should be. The way he follows Marion into town, with her constantly glancing at him in the rear-view, gives of a rather stalker-ish vibe, right up to where she's at the car dealership, where he parks across the street and leans against his car...just watching.
Our first sighting of Arbogast. Despite his suspicious nature, he ultimately turns out to be a good guy, but theres something about the way he enters getting dangerously close to the camera that creates an uncomfortable sense of claustrophobia.
The unspeakably creepy strings-only score by Bernard Herrmann. Though the trademark "Psycho" Strings are the most famous (and famously frightening) piece from the soundtrack, the film is filled with snippets of music that are just as scary, but in more subtle, more suspenseful way. Of particular note are "The City" and "The Stairs", which positively drip with anxious, quiet menace.
The Logo Joke where the drop of water in the "Imagine Entertainment" logo is replaced with a drop of blood. As if the ominous nature of the logo wasn't creepy already.
Mother's final monologue has her's and Norman's voices overlapping for a thoroughly eerie and disorienting effect.