Amnesia might be my least favorite plot twist. For the most part, when a character gets amnesia you know that the scriptwriters have run out of ideas, and that they're using a shortcut to cover up plot holes or to magic away a problem. But even when it isn't used lazily, it still feels forced to me; I understand that David Lynch's Mulholland Drive isn't using amnesia in the exact same way that a soap opera would - or rather, it is, albeit in a self aware way - but it still frustrated me to no end, because even ironic amnesia feels implausible.
Given my distrust of amnesia as a story device, I was a bit surprised to discover that I liked the Bourne Identity so much. I had put off seeing it for a long time because the basic premise of the Bourne franchise - a man is found floating in the ocean, and when he is brought back to life he discovers that he has all of the skills of a super-spy but no memory of who he is or how he got those skills - sounded cheesy to me. The film's reputation as the Godfather of Shaky-cam didn't help, either. But I have to say: the Bourne movies are better in practice than they sound on paper.
In large part, this is because they do a really good job of avoiding the pitfalls associated with amnesia. It isn't introduced as a plot twist; it's right there in the premise. That indicates right off the bat that they aren't using it as a way of weaseling out of some dead end, and that there are hard answers to the questions Bourne (and thus the audience) are asking. Also, the film suggests an origin for Bourne's specific form of amnesia that I'm sort of willing to buy: it's implied that his memory loss is a by-product of whatever process the government used to turn him into a super-spy. Yes, it's still a little too convenient, but it's not that much more convenient than most of the conventions in a super-spy movie.
In fact, the Bourne Identity turns amnesia into an asset by using it to graft a layer of enigma onto the proceedings. The film still follows the traditional beats of a spy movie, having Jason Bourne flit from country to country in an attempt to outrun both the local police who want to question him and the shadow government operatives who want to kill him, but it feels fresher than your average spy movie because it's also acting as a mystery. I suppose most spy movies are supposed to be a mystery, but I've never really tried to puzzle through the villain's plan in a Bond movie because a) the plan isn't going to make sense and b) it's going to get explained to me in due time. However, here I was consistently engaged with Bourne's search for the truth. Matt Damon plays up the frustration of his predicament in a way that makes the how and why of his origin feel like a human-sized story, even though it's really a story about a vast global conspiracy.
Furthermore, the amnesia angle actually helps out with the exposition, too. The fact that Bourne doesn't remember any of the plot points that he should logically know means that he has to ask about them. It ends up being a nice way to avoid the clumsiness that plagues spy movie scripts, because it allows for necessary information to come out as actual dialogue, not randomly regurgitated backstory.
In general, my problem with amnesia is that it pushes the story towards ridiculousness. Here, Bourne's amnesia actually does the opposite: it grounds the story by allowing him to be mystified that he can do all of these improbable things without denying him the ability to do those improbable things. Yes, it's still probably better the less you think about it, but I'll take it.
Shaky-cam, on the other hand...