Whenever you meet with a challenge there is a response. The challenge and the response constitute an experience. Generally such experience leaves a residue - which is what you have learned from that experience; this is memory. When there is a similar challenge again, the response is by the already existing residue. The residue itself is old and it translates the new challenge according to itself and the result is added to the residue. Thus, the residue gets thicker and thicker. Though the accumulation is undergoing modification, it is still old in relation to any new challenge.
     You are changing. So also is your neighbour. Yet when you meet your neighbour, you have your old picture of that person.
     This residue is a problem only when it is pleasurable or painful. If pleasurable, you leave it as it is; if painful, you do something about it. This is how you have marvellous recollections of pleasure and horrible recollections of pain. Why do you fight pain or suffering? Is not suffering only a symptom of your avoiding to face 'what is'?