“A happy man is too satisfied with the present to dwell too much on the future.”
Albert Einstein (1879–1955) German-born physicist and founder of the theory of relativity
Un homme heureux est trop content du présent pour trop se soucier de l'avenir.
From "Mes Projets d'Avenir", a French essay written at age 17 for a school exam (18 September 1896). The Collected Papers of Albert Einstein Vol. 1 (1987) Doc. 22.
1890s
Variant: A happy man is too satisfied with the present to dwell too much on the future.