The trouble with the world is that the stupid are cocksure
and the intelligent are full of doubt.
— Bertrand Russell
The Dunning–Kruger effect is a cognitive bias in which unskilled individuals suffer from illusory superiority, mistakenly rating their ability much higher than average. This bias is attributed to a metacognitive inability of the unskilled to recognize their mistakes.
Actual competence may weaken self-confidence, as competent individuals may falsely assume that others have an equivalent understanding. David Dunning and Justin Kruger of Cornell University conclude, “the miscalibration of the incompetent stems from an error about the self, whereas the miscalibration of the highly competent stems from an error about others”.
Abraham Maslow describes an insecure person as a person who “perceives the world as a threatening jungle and most human beings as dangerous and selfish; feels rejected and isolated person, anxious and hostile; is generally pessimistic and unhappy; shows signs of tension and conflict, tends to turn inward; is troubled by guilt-feelings, has one or another disturbance of self-esteem; tends to be neurotic; and is generally selfish and egocentric.” (Maslow, 1942, pp 35). He viewed in every insecure person a continual, never dying, longing for security. Alegre (2008).