One of my favourite films ever, Nolan's best film without any doubt, and easily one of the best films of the new century.
It is wonderfully engaging simply for it's novelty first time round, but repeated viewings reveal a myriad of different possible interpretations and analyses... a film that I enjoyed for so many basic reasons first time round - the casting of Guy Pearce (who I've always liked), the decision to play the film's "colour segments" in reverse chronological order (particularly beginning with the brutal murder and Lenny shaking the polaroid as the credit's role), a really realistic and innovative portrayal of memory loss and how it's dealt with and many more reasons like this - has become, on repeated viewings, one of the best films I've ever encountered, because it is so right in it's message.
Memories are rooted in perception and interpretation, and even something you thought you knew with great clarity can prove to be false. And yet, not only are memories frequently open to mistakes, they are also essential in developing and maintaining a sense of humanity and personality.
Without a past we have no way to maintain a present, let alone build a future. And the final twist that, after everything, it was Teddy who was telling the truth.
But past the deep lying themes (which took me several viewings to fully appreciate and unravel), on a superficial level, I just care about a very sad and lonely man who has lost everything, including the ability to move on. Who else didn't well up when Lenny spoke about "touching the cold side of the bed" or when he went to burn his wife's items?
All round, in many ways, a wonderful film.