The element of cruelty in both the practice and the theory of many great men is attributable to the fact that their career, unconsciously to themselves, is their revenge upon the world for what it made them suffer in youth.
Source: "Should children be happy?" [From: Mortals and Others: Bertrand Russell's American Essays, 1931-1935, v.1 (1975)]
More info.: https://russell-j.com/CHILDHAP.HTM