When I compare my agony of last year with the present, I am glad to find a wider view of things. I am slowly getting outside it all. Getting nearer the secret places of the heart also, and recognising its piteous limitations. I recognise the futility of war more than ever, and, dimly, I see the human weakness that makes it possible. For I spend all my days with people who, with a very few exceptions, are too indolent-minded to think for themselves. Sometimes I feel as if this slow and steady growth of comprehension will be too much to bear. But, if I am not mad, I shall one day be great. And if I am killed this year, I shall be free. Selfishness longs for escape, and dreads the burden that is so infinitely harder to carry than three years, two years, one year ago. The simplicity that I see in some of the men is the one candle in my darkness. The one flower in all this arid sunshine. Half-baked aspirations and reasonings are no good. I will not go mad.
—  Siegfried Sassoon, diary entry dated April 23, 1918
Went to bed at 1. Attacked by bed bugs. Fought hard till 4, slaying thousands, but the number of the enemies increasing, resolved on a retreat. The sun had risen; began by taking the sheets, coverlid, and pillows out doors, beating and shaking them well; then stripped and changed my clothes, and laid me on the floor. Got a sound nap of five hours.
— 

Private Journal of Aaron Burr. July 12th, 1809.

AKA Burr fights bedbugs, loses, and then proceeds to nap on the floor for 5 hours

I swim in the sky; I float; my body is full of flowers, flowers with fingers giving me acute, acute caresses, sparks, jewels, quivers of joy, dizziness, such dizziness. Music inside of one, drunkenness. Only closing the eyes and remembering, and the hunger, the hunger for more, more, the great hunger, the voracious hunger, and thirst.
—  Anaïs Nin, The Diary of Anaïs Nin
If I were another person observing myself and the course of my life, I should be compelled to say that it must all end unavailingly, be consumed in incessant doubt, creative only in its self-torment.
But, an interested party, I go on hoping.
—  Franz Kafka, from Diaries
How To Keep a Diary Like Virginia Woolf

“Begin by making your own diary-books. Find some old books in a second-hand shop or a car boo sale, books with good covers and bindings. Pull out some pages and fill them with your own choice of paper. Disguise your diary inside old school textbooks, the ones that used to teach grammar. Virginia Woolf was appalled by her negligent grammar. But grammar was not the point. Practice writing with and without it. Allow yourself to move. Woolf galloped through sentences in her diary, in a haphazard way. ‘It loosens the ligaments,’ she said. Her diary was somewhere she could appear ‘slovenly’ and ‘elastic’. Not everything we jot down in our diaries needs to be carefully thought out. Put on baggy clothes. Relax your mental joints. No one but you is looking. Let your brain go loose and floppy. Let your hand lead the way. Get inside your body and find a rhythm. Bring your brain into contact with your breathing. Let go.”

Sally Bayley, The Private Life of the Diary