Psychological thrillers, anyone? (+ list now!)

-Edit: Woa I got so many suggestions! You guys are AWESOME. Seriously, I'm set for the next couple of weeks! Thanks so much everybody, I really appreciate it   Now, I've made a list off all the movies that have been suggested, just so that you and I can easily come back here for an idea what movie to watch Here it goes!

Memento
Secret Window
Psycho
Identity
Pi
The Butterfly effect
Suckerpunch
The Forgotten
Black Swan
Shutter Island
The Perfect Blue
The Jacket
1408
Number 23
Se7en
Dream house
La piel que habito
Audition
Sunshine
Take Shelter
Devi
Silence of the Lambs
Session 9
The Usual Suspects
Fight Club
The Manchurian Candidate
American Psycho
The Talented Mr. Ripley
The Prestige
The Game
Primal Fear
Girl, Interrupted
Gattaca
Oldboy
Mr. Brooks
Hard Candy
Fracture
Stir of Echoes, Trapped
Primal Fear
Luther (show)
Vidocq
The Uninvited
Fight Club
The Prestige
ChinaTown
Rear Window
Strangers on a Train
Rebecca
The Devil's Backbone
Baby Blues
Donnie Darko
The Sixth Sense
The Machinist
Watchmen
A Beautiful Mind
Cemetery man
The Others
Eden Lake
Unknown
Lost Highway
Gothika
The Cell
The Orphanage/El Orfanato
Event Horizon
The Mist
Cabin in the woods
Jacobs Ladder
Dead End

Ah, who am I kidding... I will be busy with these for months I hope I've named everything!  Thanks so much again everyone, and I hope you enjoy too!

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Hi everyone!
I love these kind of movies, like Shutter Island for example, and I was wondering if anyone got any good recommendations?
The kind of movie with a lot of tension, where first you're all like 'WTH is going on here' and then at the end you're like 'ooooooooh' because you finally get it xD
So if you know one, could you please share with me? *_* Oh and, doesn't matter which language it is, as long as I can watch it with English subtitles when that's the case.

Also, happy Halloween! We don't really celebrate Halloween here but the concept is awesome nonetheless.
Unfortunately this day is very different for many people because of Sandy, so my thoughts goes to them too.

Thanks for reading <3
Lisa