Why did I write it down? In order to remember, of course, but exactly what was it I wanted to remember? How much of it actually happened? Did any of it? Why do I keep a notebook at all? The impulse to write things down is a peculiarly compulsive one, inexplicable to those who do not share it …

…

But our notebooks give us away, for however dutifully we record what we see around us, the common denominator of all we see is always, transparently, shamelessly, the implacable “I”…

– On Keeping a Notebook (1966) by Joan Didion in Slouching Towards Bethlehem, Penguin, 1974  (first published 1968).