To own or possess is to monopolize the use of something permanently. Hence the need to possess betrays a degree of insecurity. Possession is a way of ensuring access to whatever it is we want to use or enjoy: we are so anxious that the object be there when we want it that we are willing to insist that it be there even when we don't want it. Thus we have food on our shelves when we're not hungry, clothes in our closets that we're not wearing, cars in our driveways that we aren't driving, and so on.
The rationale is that when we do want to eat, dress, or drive, we won't have to waste time looking around for the food, clothing, or transportation. This time saving is questionable, as we shall see, but it expresses the sense of urgency that lies behind the compulsion to possess.
Source: Wealth Addiction
I think this has a lot to do with "books on the shelf that I'm not reading -- but tomorrow or next day I might just want to"...