Memento

Was it Sammy, Lenny... or was I the one with amnesia? It's genuinely an incredible experience. Throughout the film, there were several moments where I was convinced I had finally figured out why things happened and how everything fit together—only to realize I was completely wrong. That happened to me at least three or four times, and it's exactly what makes the story so gripping. I also love how Nolan once again showcases his fascination with time (I'm exactly the same), which earns the film a few extra points from me.