Nostalgia, and wanted things

Nature of nostalgia suggests a few profound things about the true nature of human recognition and memories. For example, sometimes I feel an almost irresistible nostalgia to the days I can objectively say as one of the worst humanely possible conditions one can encounter. The horror, the anxiety, the sadness and the utter feeling of powerlessness. All is subdued within certain lights and certain strange winds, the quiet swaying of trees and the touch of cool twilight wind which turns the whole horrible experience into a perverted romance, making me long for the day even for a single moment. As such, the nature of memory and nostalgia is quite peculiar. I think except under very limited circumstances the nature of memory might as well have only a superficial resemblance to the conventional 'copy of reality' sense we get from the analogies comparing human brain and its functions to that of computers. In fact, first hand experience with a human brain (I have one in here, I assure you) makes me think what we consider to be specific and clear-cut functions of brain might not be as clear cut as usually believed, although I do not quite believe that the structure and function of the brain is entirely holistic as some proponents of the theory seem to suggest. It is more like one function complementing each other in a sort of linked reaction, one thing always verging on the territory of the other, physical and mental reaction accompanying the other (physical pain and memory?) for no sound physiological reason. In such perspective, it is not that memories and processing capabilities come together to build a conscious system, but the conscious system forms aspects of memory and processing ability as the original system gradually becomes specialized with time/evolution.
If certain quality of emotion and reaction can be expected regardless of actual physical situation being experienced, such as an aesthetic thrill or a dramatic flair in situations of distress or sadness, then what does that tell us about the nature of human exprience on the more profound and general level? Would that mean human perception and reaction is entirely separate from the physical circumstances we subject ourselves to? Wouldn't that mean that the sense of beauty exists separate from the 'beautiful thing' being observed at the moment, and that while certain quality for evoking a response may be present in objects, there is no staying power in such evoked responses since the response have nothing to do with the quality of the physical object, its 'being' in the first place? If that is the case, then it is impossible for things in this world to remain beautiful forever, in the eyes of everyone, of everything.
However, even if that is the truth, what can I make of it in connection to certain philosophies behind the beauty of photography and abstract expressionistic art, where certain moments or (rather hazy) units of human response in front of the object-world are sought out as sort of atoms of human experience and thought?