"Must Haves" for the perfect horror flick. Can you think of any more?

Question

My list starts here:
A group of people (friends, classmates, co-workers, etc.)
One "nice" couple.
One "horny" couple.
A dorky friend.
A jock.
A hot girl.
A smart friend.
A mean boss/teacher.
One barking dog.
Electric outage.
Small town.

What is missing?

I'm not writing a horror flick, this is just for fun.

Answer 1

The "crazy" old stranger who warns: "You don't know what yer' dealin' with! Turn around and go back to where you came from!"
The prankster friend.
The car that won't start or the jammed door that doesn't open til the very last second.
The thick-headed sheriff who won't believe the victim's story.
Dead body
The survivor (to return for the sequel)