Do we have a valid point to make? Did the other person act in a manner that is selfish or, worse, abusive? Are we unsure? If so, then we should offer our point and ask them to explain themselves. If they refuse to do so, then they may have just confirmed our suspicion. After all, we always deserve to know their intention. And if they refuse to answer our civil questions, then we have the right to leave the interaction and not return until they are willing to explain the origin of their action or statement (or inaction or silence as the case may be). The validate feeling section has more information to help you determine when a complaint is in order. After all, if you can't justify the feeling, you don't have the basis for making your dissatisfaction someone else's responsibility.