Over confidence is a peculiar feature in humans which has sometimes made us do phenomenal things and also allowed us to make colossal mistakes. It is true that in order to do something totally remarkable & unique we need to have a high level of overconfidence in our ability to achieve. This overconfidence comes from our optimism to do something. Overconfidence in this context is very useful which tends to motivate us & keep pushing till we succeed. It is like Thomas Edison whose optimism to tinker with the light bulb & his overconfidence in his abilities to actually make it, led to a remarkable invention.
The dark side of overconfidence comes into picture when our overconfidence hurts us by blinding us to very obvious errors in judgements. It is like watching a Superman cartoon & going on the rooftop to see if we can fly too. Generally the dark side of overconfidence becomes obvious only in hindsight. But we need not be suckers to overconfidence all the time. Becoming aware of where we tend to be overconfident can protect us from making a rash decision.
In this phenomenal book Mastermind – How to think like Sherlock Holmes written by Maria Konnikova she uses the great fictional detective’s ability to solve tough criminal cases to explain how we can train our brain to become as sharp as Sherlock’s. In one chapter she mentions how even someone as sharp & mindful like Sherlock Holmes can fall prey to the dark side of Overconfidence. She lists four major instances where overconfidence has been most prevalent.