Okay, so I usually don't get scared ever, by anything. But then my friend brings this bootleg copy of a movie called "The Descent" over and we watch it.
I have never felt so claustrophobic in my life, the movie made me feel sick. I couldn't believe what I was watching and how real and terrifying the subject matter was. If you are looking for a scary movie to basically scare the living shit out of you (and all your friends) watch this movie: "The Descent"