Memento Theme of Manipulation

Manipulation is pretty much the name of the game for all the characters in Memento.

Teddy manipulates Jimmy and Leonard so he can make money; Natalie manipulates Leonard for protections, Leonard's/Sammy's wife manipulates Leonard/Sammy as a last resort to bring him back; even Leonard manipulates himself so that he can control his future thoughts and actions.

Leonard's anterograde amnesia has left him a malleable lump of clay that everyone tries to mold to their desires.

1. Who is the most manipulative character? Teddy? Natalie? Leonard himself?
2. Manipulation has such a negative connotation, but is all manipulation in the film necessarily morally wrong? Do some characters manipulate for the good of others?
3. What differences are there between the ways Natalie manipulates Leonard and the ways Teddy manipulates him?

Leonard is the main culprit of manipulation. He lets himself live a lie, purposefully skirting dealing with his difficult past and not allowing himself to move on. It's not amnesia that prevents Leonard's healing; it's all the lies he tells himself.

Leonard's manipulation is necessary for his living a normal life. Unlike the rest of us, Leonard can't accumulate memories, and it's difficult for him to carry out tasks over long periods of time. Instead of thinking about it as manipulation, we can think of it as preemptive decision-making.