but all absent good does not at any time make a necessary part of our present happiness, nor the absence of it make a part of our misery.
 John Locke, An Essay Concerning Human Understanding (1689). copy citation

Context

“though every little trouble moves us, and sets us on work to get rid of it. The reason whereof is evident from the nature of our happiness and misery itself. All present pain, whatever it be, makes a part of our present misery: but all absent good does not at any time make a necessary part of our present happiness, nor the absence of it make a part of our misery. If it did, we should be constantly and infinitely miserable; there being infinite degrees of happiness which are not in our possession. All uneasiness therefore being removed, a moderate portion of good serve at present to content men;” source