If assertive behviour is about standing up for yourself, when does assertiveness become aggressive behaviour?
Aggressive behaviour however, is often driven by anger and an unwillingness to listen to anyone else. Agressive behaviour is less about discussion and more about trying to force people to agree to your outcome. There are some people who confuse assertiveness with aggression, mistakenly believing that they can't compromise and still be assertive.
Assertive communication is based upon both self-respect and due respect for others and their opinions.
Aggressive people need to learn to listen and they also often need to develop greater self-control. They tend to get frustrated too easily and have a short fuse. Unfortunately they have to unlearn many bad habits and cultivate a more balanced approach to dealing with people with more tact and patience.
An aggressive person will only start making genuine efforts at personal change when they recognise that their approach is destroying relationships with the people around them, at the expense of achieving their goals.
It's not much point achieving your goals however, if no-one wants to enjoy it with you. Sometimes, the very aggressive person may need to learn anger management techniques as part of improving their self-control.