Aggressive behavior, as the word suggests, is a forceful and offensive behaviour. In negotiation, aggressive behaviour usually involves a "demanding" request toward the other parties. For examples, aggressive negotiators might say something similar to: "I want.", "I must have", "you should," etc. They sometime will pressure the other parties, in achieving the results that advantageous to them. This behaviour which usually considered ineffective by many people, however, can benefit oneself if used correctly. This is because being aggressive allows one to be strong in his or her standpoint. The person who takes an aggressive approach is basically telling the others, "This is what I must have, no matter what!". In certain scenario, by not backing down in negotiating, we can gain more on what we want instead of give in into the other parties. In other words, we can get something for nothing from the others. Such behaviour also allows the other parties to understand what you want and what you need. Usually, during aggressive negotiation, we will have to make our points clear by demanding what we want. From the viewpoints of the other parties, they will understand what is needed by us, in turns making offer which will benefit us – if not both side of the parties – to achieve a mutual outcome by the end of negotiation.
However, being aggressive in negotiation could in result in several disadvantageous situations to the users. As an aggressive approach involves demanding what you want and being strong on your standpoint, such approach could causes defensive behaviour on the other parties. For example, when you demanding what you want from the other parties, they will think, "Who they think they are?", "I don't have to do as what they told me to do, "I didn't get anything in return if I give you what you want, so why bother?".