Overconfidence is ruinous.
Overconfidence usually ends in setbacks. It is never fruitful. It occurs to ordinary people in general. 
Ordinary people are made by their environments, drawing meagerly on their inner qualities. They misunderstand what confidence is and how it evolves. 
They flow without eliminating flaws from any process. This approach leads to false confidence. Winning on a few occasions makes the common people take future courses for granted. This proves to be ruinous. 
The victims of overconfidence are habitually inaccurate in relating the happenings. They don’t venture to cross-check any information. They know the least, but they divert their energy to impress others as masters of the hot issues affecting society. 
Let us understand that confidence is nurtured. The process of gaining confidence is full of rough edges. Smoothness comes at the end. Confident people first learn how to regulate their thoughts, emotions, and feelings. After a long battle inside, they gather confidence. They do everything to keep the confidence intact and rewarding. 
Confident people believe in being original and setting their own unique pattern in dealing with day-to-day affairs. They learn from mistakes, and they dare to rise even after a deep fall. This adds to their confidence more than other methods. 
Ordinary people oscillate between no confidence and overconfidence and don’t know how to balance this to and fro. They remain immature, though they falsely believe they are mature. 
Take writing skill as an example. Trace the steps we have taken from learning the alphabet to this stage. The same thing happens when you gain confidence in other skills. 
We are the best judges of our degree of confidence. When we wear the mask of confidence, in contrast to our realities, we make blunders.