Many people, who have a ‘know-it-all,’ persona; whether a Webster definition, or who pretends to know more than anyone else; have one personality trait in common, narcissism. Hidden behind the need to let the world know exactly how smart, funny, interesting or great she/he is, is the need to convince him/herself of their value. All know-it-alls suffer from a lack of self-confidence, and what they seek, through their tireless efforts to impress, is usually the need for approval and validation.