How many people do you now with Dunning-Kruger effect? :-)
The Dunning–Kruger effect is a cognitive bias in which unskilled individuals suffer from illusory superiority, mistakenly rating their ability much higher than is accurate. This bias is attributed to ametacognitive inability of the unskilled to recognize their ineptitude. Actual competence may weaken self-confidence, as competent individuals may falsely assume that others have an equivalent understanding.
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".