Dunning–Kruger effect: Underestimating Own In/Competence
The Dunning–Kruger effect is a cognitive bias wherein unskilled individuals suffer from illusory superiority, mistakenly assessing their ability to be much higher than is accurate. This bias is attributed to a metacognitive inability of the unskilled to recognize their ineptitude. Conversely, highly skilled individuals tend to underestimate their relative competence, erroneously assuming that tasks which are easy for them are also easy for others.
.. If you’re incompetent, you can’t know you’re incompetent. […] the skills you need to produce a right answer are exactly the skills you need to recognize what a right answer is.
—David Dunning