Dunning-Kruger effect
(reading time – 20 sec.)

The Dunning-Kruger effect occurs where people fail to adequately assess their level of competence — or specifically, their incompetence — at a task and thus consider themselves much more competent than everyone else. This lack of awareness is attributed to their lower level of competence robbing them of the ability to critically analyse their performance, leading to a significant overestimation of themselves.

In simple words it's "people who are too ignorant to know how ignorant they are".

Topic: #CognitiveBiases
Source: rationalwiki.org