In the field of psychology, the Dunning–Kruger effect is a cognitive bias wherein people of low ability suffer from illusory superiority, mistakenly assessing their cognitive ability as greater than it is. The cognitive bias of illusory superiority derives from the metacognitive inability of low-ability persons to recognize their own ineptitude; without the self-awareness of metacognition, low-ability people cannot objectively evaluate their actual level of competence.
https://en.m.wikipedia.org/wiki/Dunning–Kruger_effect
Why incompetent people think they're amazing (5 minutes):
https://youtu.be/pOLmD_WVY-E