Let us say that at your place of work you are having issues with someone making unwelcome advances. This person is highly placed in the company, and you are afraid to say anything because she has the power to demote you, or even fire you.
If you have made a complaint at work related to Equal Employment Opportunity laws, you may be at risk for retaliation from your boss. A boss who fires an employee after that person has made an EEO complaint is an obvious form of retaliation. However, sometimes the retaliation is not as clear.
If you have a problem at work and decide to take action, most likely your first thought is to go to human resources. This is a natural inclination for most employees. But depending on the details of your situation, it is not always a wise decision. In fact, it could end up hurting you in the long run.