Memento

Because he cannot form new memories, every conclusion he makes becomes permanent, even if it’s wrong. he chooses what to write down, what to leave out and how to phrase it. We’re discovering the reality the same way he discoveres his. At the start of the film which is actually the ending, Lenny kills Teddy. He finished the fake puzzle he created. Teddy is not lying all the time. Leonard learned to manipulate himself. He starts creating lies and a fake investigation for his future self just to have a purpose. details from Leonard’s life leak into Sammy’s story (the insulin, the wife, the test). This suggests Leonard transferred his guilt in an invented figure.  Once Leonard proves he can lie to himself on purpose, there is no remaining stable truth in the story. only behavior repeating inside a loop.