Tell mother that however dogs and samovars might behave themselves, winter comes after summer, old age after youth, and misfortune follows happiness (or the other way around). A person can not be healthy and cheerful throughout life. Losses lie waiting and man can not safeguard against death, even if he be Alexander of Macedonia. One must be prepared for anything and consider everything to be inevitably essential, as sad as that may be.
Letter to his sister Maria Pavlovna Chekhov (November 13, 1898)