The man who underestimates himself is perpetually being surprised by success, whereas the man who overestimates himself is just as often surprised by failure.
 Bertrand Russell, The Conquest of Happiness (1930). copy citation

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Author Bertrand Russell
Source The Conquest of Happiness
Topic success failure
Date 1930
Language English
Reference
Note
Weblink http://russell-j.com/beginner/COH-TEXT.HTM

Context

“Pleasures of achievement demand difficulties such that beforehand success seems doubtful although in the end it is usually achieved. This is perhaps the chief reason why a not excessive estimate of one’s own powers is a source of happiness. The man who underestimates himself is perpetually being surprised by success, whereas the man who overestimates himself is just as often surprised by failure. The former kind of surprise is pleasant, the latter unpleasant. It is therefore wise to be not unduly conceited, though also not too modest to be enterprising. Of the more highly educated sections of the community, the happiest in the present day are the men of science.” source