Karma is very important in human life. Life without Karma is useless or purposeless. Bhagwad Gita suggests Karma or action should always be our priority. By nature, Karma is a mixure of Shat and Ashat. Every action essentially has positive and negative effects. Still, Classical Texts suggest doing the righteous action.
Good and bad karma have their own type of results. Good action brings good result and bad action leads to bad result. But both (good and bad) actions are bondage to soul. According to Bhagwad Gita, our soul will not have bondage if we do not expect results of our action. In this way, Action without attachment, expectation of Profit & Loss, happiness & sorrow, prestige and insult etc is called Karma Yoga. Nishkama Karma (action without desire) is more necessary than performance of duties with expectation; which is accepted as an essential tool for self-realization.