Habit weakens all things; but the things that are best at reminding us of a person are those which, because they were insignificant, we have forgotten, and which have therefore lost none of their power. Which is why the greater part of our memory exists outside us, in a dampish breeze, in the musty air of a bedroom or the smell of autumn's first fires, things through which we can retrieve any part of us that the reasoning mind, having no use for it, disdained, the last vestige of the past, the best of it, the part which, after all our tears sem to have dried, can make us weep again. Outside us? Inside us, more like, but stored away from our mind's eye, in that abeyance of memory which may last forever. It is only because we have forgotten that we can now and then return to the person we once were, envisage things as that person did, be hurt again, because we are not ourselves anymore, but someone else, who once loved something that we no longer care about. The broad daylight of habitual memory gradually fades our images of the past, wears them away until nothing is left of them and the past become irrecoverable. Or, rather, it would be irrecoverable, were it not that a few words (such as "chief undersecretary at the Postmaster General's") had been carefully put away and forgotten, much as a copy of a book is deposited in the Bibliotheque Nationale against the day when it may become unobtainable.
--Marcel Proust, In the Shadow of Young Girls in Flower