Emotional Memory hypothesis

I just thought of a relationship between emotion and memory: Since all memory are seem to be colored by affects, I suppose they are there precisely because they are emotional in nature. Emotion is not just a part of encoding process, it is also active in maintaining the content there. So when Psychoanalysis talk about Unconscious and Complex as some kind of mysterious psychological process, now I would suggest that Complex maybe simply a neurological mechanism evolved to preserve the memory, it has to be actively interfere with the present in order for that memory content to exist. Memory, therefore, I suppose could NOT be emotionally neutral. Unconscious process maybe simply a neurological mechanism that operated since the beginning of human race. Memory maybe a by-product derived later to serve the emotional system. We could thus now trying to see Psychoanalytic theory in light of its neurological correlate.