This explains much-----The more inept you are the smarter you think you are

BBC - Future - Health - The more inept you are the smarter you think you are:
"You're pretty smart right?
Clever, and funny too.
Of course you are, just like me.
But wouldn't it be terrible if we were mistaken?
Psychologists have shown that we are more likely to be blind to our own failings than perhaps we realise. This could explain why some incompetent people are so annoying, and also inject a healthy dose of humility into our own sense of self-regard.

In 1999, Justin Kruger and David Dunning, from Cornell University, New York, tested whether people who lack the skills or abilities for something are also more likely to lack awareness of their lack of ability. 
At the start of their research paper they cite a Pittsburgh bank robber called McArthur Wheeler as an example, who was arrested in 1995 shortly after robbing two banks in broad daylight without wearing a mask or any other kind of disguise.
When police showed him the security camera footage, he protested "But I wore the juice".
The hapless criminal believed that if you rubbed your face with lemon juice you would be invisible to security cameras."