Those whom fate has dealt hard knocks remain vulnerable for ever afterwards. Beware of Pity

“A slight blow for me: a telegram from Paris, informing me that an old uncle of mine (…) is arriving tomorrow evening. It is a blow because it will take time and I need all the time I have and a thousand times more than all the time I have and most of all I’d like to have all the time there is just for you, for thinking about you, for breathing in you. My apartment is making me restless, the evenings are making me restless, I’d like to be someplace different and I’d prefer it if the office didn’t exist at all; but then I think that I deserve to be hit in the face for speaking beyond the present moment, this moment, which belongs to you.” (6 July 1920) Letters To Milena

Never esteem anything as of advantage to you that will make you break your word or lose your self-respect. Book III

Behavior evolves through natural selection, just as anatomy does. Hence if sex is enjoyable, natural selection must have been responsible for that outcome. Why Is Sex Fun?: The Evolution of Human Sexuality