Dunning–Kruger effect:

The Dunning–Kruger effect is a cognitive bias manifesting in unskilled individuals suffering from illusory superiority, mistakenly rating their ability much higher than is accurate. This bias is attributed to a metacognitive inability of the unskilled to recognize their ineptitude. Conversely, people with true ability tend to underestimate their relative competence based on the erroneous or exaggerated claims made by unskilled people.

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".

^{Interesting: Illusory superiority | Overconfidence effect | Hanlon's razor | I know that I know nothing}

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