"If you own a teacup that is very precious to you, you have two choices: you can be obsessively careful with it, and live in fear that you'll drop it, or someone will chip it, or an earthquake will come and it will fall out of the cabinet. This object, intended to bring you pleasure, can become a burden.
Or, you can imagine that it is already broken -- because in an important sense, it is. It's sure to break someday, just as you're sure to die and the universe is sure to come to an end. Then, every time you drink from the cup will be a pleasure, a gift from the gods, a special reunion between you and something you had lost. You will be sure to appreciate every chance you have to use it, but having already said goodbye you will not need to use it with fear."
When I read this to Jeff, he went to the fatalist extreme, asserting that if this is the case, then why not commit suicide now, if all is already lost? Non-attachment is not about grieving over what is lost, it is about celebrating the joy when it is found. And knowing that moment will not last. Practitioners who have mastered mindfulness (of which I am not one) are so immersed in the moment that the moment prior and the one to come are not relevant. Whether the teacup exists in the next moment does not matter (or whether or not it existed in the moment previous) what matters is that in this moment the teacup exists and that is what is to be celebrated.
I used to hide $5 bills in my pockets. Obviously I knew I had done it. And the money was always mine. Yet imagine the joy I experienced upon reaching into my pocket and finding money!! While it seems a bit counter intuitive to use money as an example of non-attachment, to me that moment is what this koan is addressing.