Many people pretend to have it, less actually do and far Fewer even know enough about themselves to figure out why they should but its the make or break difference between many peoples entire lifestyles both Personally and Professionally.
Confidence will make you hold your head high, it will strengthen your convictions and drive you further in your mission at any task, but by definition you must first Know yourself. Some people take the "Fake It til you Make it" route and choose to deceive others by over compensating confidence into what appears to be a cocky behavior which is so Blatantly transparent and counter productive to the point they start to believe their own facade. This is the absolute worst way to better yourself, simply because you think you already have an stopped trying to. Instead take time to do some self revelation, humble yourself and do more to actually reach your full potential. Study yourself and be proud of the good you have accomplished along with taking stock of the laundry list of negatives you can augment into a positive quality, and ensure you do so continually. The moment you don't know enough about you, your accomplishments and faults is the day you have failed yourself. Without Knowledge of Self, Confidence is nothing more than Delusion; Don't let a Mirage of the ideal you quench the thirst you possess in progressing towards the actualization of it.