Amnesia is one of the favorite themes of Hollywood directors. For instance, The Great Dictator, Memento, Mulholland Drive, Eternal Sunshine of the Spotless Mind, or the Bourne Trilogy, talk about memory, and especially about amnesia. Some are close to reality and some are really far from reality, driving myths about memory and amnesia.
If you have watched the Bourne Trilogy, you know that amnesia is the main theme of these three movies. And these movies are pretty accurate about memory and the effects of a loss of memory. Indeed, even if it deals with retrograde amnesia - the loss of some memories of the past (and here all of the memories of the past, which do not seem very realistic) - which is a really rare kind of amnesia, most part of the movies promote true ideas.
For instance these movies make a distinction between implicit and explicit memory. Implicit memory includes all memories we do not deliberately remember or reflect on consciously. Explicit memory includes all memories we recall intentionally and of which we have conscious awareness. Remember the beginning of the first movie of the trilogy (use your memory!), first scene, when Jason Bourne is able to fight, and have exceptional skills in this field, even if, as we'll see right after, he does not remember anything of his past. This is a perfect example of implicit memory, which is not affected when someone suffers from amnesia.
The Bourne Trilogy is also close to reality about the recovery from amnesia. Recovery occurs gradually during all the three movies, Jason Bourne learning little by little who he is really, a former CIA secret agent, and scientific studies prove that, indeed, memory recovery from amnesia tends to occur gradually, if at all.
On the other hand Hollywood creates movies like Eternal Sunshine of the Spotless Mind. Everything in this movie is totally crazy. It is obviously impossible to come into someone's brain and erase memories which are linked to a specific person. Indeed, even if it is proved that some drugs like propanolol can hide traumatic memories, until now no one found how to erase painful memories. And as it is shown in this movie, maybe it would be a very bad idea to be able to do it.