One can say that optimists are, in general, extremist theoreticians. The consequences of this have been well put by Georges Sorel in writing of the Jacobins: “If, unfortunately, they find themselves armed with great political power allowing them to realize an ideal that they have conceived, optimists may lead their country to worse catastrophes. They are not long in recognizing, indeed, that social transformations are not achieved with the facility they had expected; they attribute their disappointments to their contemporaries, rather than explain the march of events in terms of historic necessity; thus they end by attempting to remove those people whose evil desires seem to them dangerous to the welfare of mankind. During the Terror, the men who spilt most blood were exactly those who had the keenest desire to enable their fellow-creatures to enjoy the golden age of which they had dreamed, and who had the strongest sympathy for human misery. Optimistic, idealistic, and sensitive, as they were, these men showed themselves the more inexorable as they had a greater thirst for universal well-being.”
(Robert Michels, “The Sociological Character of Political Parties.” In: First Lectures in Political Sociology. Minneapolis: University of Minnesota Press, 1949, p. 140).