In order to truly succeed in life - you must know yourself. In order for your relationships to thrive - you must know yourself. In order to achieve ALL things that you want for you and for your loved ones - you must know Yourself! Before you can get anywhere worth going in this world, you have to know other people (how they feel, what makes them feel that way, what they want....). It matters not if you're a teacher, entrepreneur, salesman, chef, doctor, lawyer or writer. You'll simply never be of use to anyone unless you know them.
And, as the saying goes, you'll never know others until you know yourself. *Self knowledge is at the point where wisdom meets happiness. Take a close, careful, conscientious look at yourself.