To keep our ancestors alive, Mother Nature evolved a brain that routinely tricked them into making three mistakes: overestimating threats, underestimating opportunities, and underestimating resources (for dealing with threats and fulfilling opportunities).

   (Rick Hanson, neuropsychologist) #quote

At our core we humans are wired to avoid risk. We evolved this way because to our ancestors, it was more costly to miss the sign of a predator (threat) than to miss the sign of food (opportunity).