"People who think their opinions are superior to others are most prone to overestimating their relevant knowledge..."

ProTip:
When you start to think everyone else is wrong it is time to either:

1) declare yourself the anointed one, put the crown on your own head, à la Nappy I, and stride forth or
2) take a moment and reflect on how you came to this conclusion.

From the British Psychological Society's Research Digest:

We all know someone who is convinced their opinion is better than everyone else’s on a topic – perhaps, even, that it is the only correct opinion to have. Maybe, on some topics, you are that person. No psychologist would be surprised that people who are convinced their beliefs are superior think they are better informed than others, but this fact leads to a follow on question: are people actually better informed on the topics for which they are convinced their opinion is superior? This is what Michael Hall and Kaitlin Raimi set out to check in a series of experiments in the Journal of Experimental Social Psychology.

The researchers distinguish “belief superiority” from “belief confidence” (thinking your opinion is correct). Belief superiority is relative – it is when you think your opinion is more correct than other people’s; the top end of their belief superiority scale is to indicate that your belief is “Totally correct (mine is the only correct view)”.

The pair set out to find people who felt their beliefs on a variety of controversial political issues (things like terrorism and civil liberties, or wealth redistribution) were superior, and to check – using multiple choice quizzes – how well they were informed on the topics about which they held these superiority beliefs. 

Across five studies Hall and Raimi found that those people with the highest belief superiority also tended to have the largest gap between their perceived and actual knowledge – the belief superior consistently suffered from the illusion that they were better informed than they were. As you might expect, those with the lowest belief superiority tended to underestimate how much they knew....

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If you choose the first option above, make certain that your credit and supply lines are in place before striding forth.

Also, double-check that the stove is turned off.