Complete ignorance breeds confidence… The Dunning-Kruger effect is a cognitive bias in which low-ability individuals suffer from illusory superiority, mistakenly assessing their ability as much higher than it really is.
Watch Stephen Fry put it in current affairs perspective at http://mashable.com/2017/05/11/stephen-fry-donald-trump-animation/ 
Stephen Fry uses psychology to take down Donald Trump
This is fascinating.