A lot of young programmers believe they have some good programming skills. Then we can build a good application which a lot of people will buy that. Let’s start a business. In the most of cases i heard, we built a good application,but only they liked their software. Building a good application only reqiures good programming skills. The most important skills is understanding what your users like and hate. Not just what you like.
Thus, that is important to know your users.