Paying the right amount of tax is a social responsibility to the country. The taxes we pay will go to the government funds that will be used in developing and improving building roads, schools, better government salaries and improve government service. And because of those factors can help attract more investors and jobs. More people having jobs means more people having money to spend which will directly or indirectly improve business as well.
On the other hand, if most of the income earners will illegally reduce their amount of tax obligation, the government will resort to private or foreign loans in order to govern the country. And there will be lesser funds to build roads, schools, infrastructure, lower wages that decrease morale which leads to poor government services. That will cause continues poverty and high unemployment rate that will result to crime increase.