The idea that our subconscious mind records everything perfectly has been around for a very long time. Using this untrue myth, it is claimed that you can remember anything perfectly from your past (and sometimes your past life), from where you left your key's, to names or faces of people involved in a crime, well almost anything you once saw or heard.
Sir Frederic Charles Bartlett (20 October 1886 – 30 September 1969) was a British psychologist and the first professor of experimental psychology at the University of Cambridge. As early as 1932, Barlett showed that memories are encoded into individual and unique impressions based on schema's. A schema is a structured cluster of pre-conceived ideas and mental structure that represents some aspect of the world. Additionally it was shown that memories are recalled affected by schema as well. So your memory of any event, is changed to fit into what you already believe to be true about the world. Almost NO memory, and particularly memories longer than a week, or ones that have been reflected on or worried about will represent the exact (or sometimes close) reality.
This is why, 10 eye witnesses to a crime will have 10 different versions of events. This is why you argue with someone about what he or she said at a conversation you were both in. The human memory and the subconscious mind does not record everything perfectly; far from it. Our memories are scattered bits and pieces that are remade to fit what we already know. Anyone who has had to study for a test knows that it can take several attempts to learn information, or watching a movie a few years after the first time and noticing differences.
Elizabeth F. Loftus is an American psychologist and expert on human memory. She made her career out of consistently showing how memory can be changed by providing misinformation and how easy it is to create false memories that people will swear are true and they lived the experience. In fact hypnosis to a certain extent is used to create false memories to create specific and desired results.