Another one which gets to me:
– When the killer or other character is rendered unrecognizable by a mask or, as in the case of Urban Legend, a raincoat’s hood.
Sorry to pick on poor Princess Buttercup again, but the poor girl just isn’t all that bright. Her “true love” is completely disguised by a black cloth mask which covers his eyes and bridge of his nose. (You know, my dog is like that. If you put on a hat, she’ll bark at you.)*
–When people being stalked by a killer split up, presumably so it’ll be easier for him to pick them off one by one. And no one thinks to get a tire iron out of the car, or pick up a stout tree limb to use as a club. When being chased through a building, it never occurs to them to look for a phone and dial 9-1-1. (Even if you just leave it off the hook, the cops will come.)
–Ghosts who must be ever-violent and scary during the first 3/4 of the movie until the protagonist figures out what help they need. At this point, the ghost is free to explain the whole deal, offer assistance, or turn otherwise benevolent, but before that, they can only throw people against walls (Gothica) or write scary, incomprehensible messages on foggy mirrors. (Never anything like, “Hey, Ghost Lady here. I need you to help catch my killer. Thanx. P.S.-- It’s your husband.”)
*I imagine Halloween would be a lot of fun at the Buttercup/Westley household.
*Westley comes out of the bedroom dressed in his ubiquitous pirate costume. (He goes as the Dread Pirate every year.) “Ready for the party, honey? Buttercup? What’s wrong?”
Buttercup: “Who are you and how do you know my name? You’d better get out of here before my husband gets back!”
Westley pulls off the mask. “Buttercup, it’s me.”
Buttercup throws herself into his arms. “Oh, Westley, my darling! Thank God you’re here! There was a strange man in here a moment ago and I was terrified!”*