Thiel has a good chapter on dichotomizing optimism/pessimism as it relates to building the future in his Zero to One book. Someone else can probably quote it be

Thiel has a good chapter on dichotomizing optimism/pessimism as it relates to building the future in his Zero to One book. Someone else can probably quote it better, but it basically boils down adding a definite/indefinite qualifier also. He posits: - Definite pessimists have a concrete negative potential future in mind and often work to subjugate it - Indefinite pessimists have a vague "the future looks negative" and don't act on concrete plans to improve it - Definite optimists have a concrete positive potential future in mind and often work to make it a reality - Indefinite optimists often have a vague "everything will be fine" mindset and rely on others to make that a reality On a general sense, I'd wager that both optimists and negatives are a good idea to have at the collective level, as both are driven by similar but different motivations. I'd say it's the definite subsets of each group that are "realistic" and "useful" as it pertains to the future, rather than either larger group as a whole.