Why Knowing YOURSELF is IMPORTANT?

We may have heard this from few intellectual people around us who say ONE MUST KNOW HIMSELF. Though that appears to be great words of wisdom but somehow it does not make much sense while listening to them. So let us talk about the bigger picture. The bigger picture of the whole thing is that IT REALLY DEPENDS ON THE NATURE OF THINGS THAT YOU ARE INVOLVED IN based upon which one actually realizes the importance of knowing himself. By the nature of things I broadly mean the duration of the existence of some work or feeling that one does or one endures respectively. If some work is of a very short duration and you are going to be back to your LOVABLE LIFESTYLE after a predestined duration of time, then whether you actually love the job or not or whatever dullness is associated with it, will not affect you at all. But if the work does not go with your personality or you get bothered while doing it and still you have to be involved in it with undetermined duration of time then it can be really bad. The sense of uncertainty of its completion can really shiver you from your insides. And hence if one knows himself then before committing to any long term thing he can think of possible ways that he will be able to use to calm himself and make him remain at peace while doing that complex work. So that later on when you can't quit due to some reason then you don't become dysfunctional out of anxiety and nervousness that is caused due to blank mind though mind must be working to get things done.
Thus Knowing yourself actually helps to make more conscious decisions and not fall apart when you go through tough experiences.