A person unaware his confidence exceeds his talent [duplicate]
Solution 1:
This would be an example of the Dunning-Kruger effect:
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 that are easy for them are also easy for others.
Solution 2:
A sufferer of Dunning Kruger syndrome.