Memento (2000)
[spoilers ahead!]
"The world doesn't just disappear when you close your eyes, does it?"
Our memory's not perfect, but you can get around that. Sometimes. But then what's the clincher? The routine and tricks you've built up? You? Or the company you keep?
Some say that because the movie doesn't work when played linearly, that it's a "filmmaker's conceit", then Memento is fundamentally just a gimmick. But I'd argue no, that's what makes the movie great. Because the plot is bound to the structure, by definition it's not a gimmick, more than a pointless trick.
The movie's two parts reflect Leonard's fractured understanding of who he is. There's the black & white part, where the movie stays linear to let him narrate about his past life (as he remembers it, at least). And there's the color part, sequenced in reverse. We get put in Leonard's shoes as each scene starts and he (and the audience) have no idea how he got there, and have to figure out as he goes along and through the notes he's written.
Leonard's condition makes his situation as sort of an inverse Groundhog Day: time and place keeps moving, but his memory doesn't. When he looks at life down his horizon, there is only the few minutes he can live in before he forgets. It makes him vulnerable, both to others' manipulation and his own mistakes.
So when it's revealed that he's stuck in a trap, we understand when he lies to himself. My only issue with Memento, is that the reveal was done by Teddy, the guy who admits he's using Leonard's condition for his own gain. I just didn't trust him when he said all those things at the end. But other than that, it's an incredible watch. Few movies marry the 'how' with the 'what' of its storytelling in such an elegant manner.