This explains a lot

The Dunning-Kruger effect is an example of cognitive bias in which people who are worst at a task show the most illusory superiority, rating their own ability as above average.

Hypotheses

The phenomenon was demonstrated in a series of experiments performed by Justin Kruger and David Dunning, both of Cornell University. Their results were published in the Journal of Personality and Social Psychology in December 1999.

Kruger and Dunning noted a number of previous studies which tend to suggest that in skills as diverse as reading comprehension, operating a motor vehicle, and playing chess or tennis, "ignorance more frequently begets confidence than does knowledge" (as Charles Darwin put it).[2] They hypothesized that with a typical skill which humans may possess in greater or lesser degree,

1. Incompetent individuals tend to overestimate their own level of skill.
2. Incompetent individuals fail to recognize genuine skill in others.
3. Incompetent individuals fail to recognize the extremity of their inadequacy.

Dunning-Kruger effect, Wikipedia