The primary difference between being assertive and being aggressive is the motivation. An assertive person establishes boundaries and states opinions while respecting others. An aggressive person is wants to dominate others, with behaviors that destroy the boundaries of other people and stifles open discussion.

Passive people who are the willingness to accept whatever anyone else says or does are easy targets for aggression and can be frustrating for assertive people who believe that everyone has a right to establish their own boundaries and state their own opinions.

People may experience different levels of assertiveness, passivity, and even aggression in different circumstances and at different times in their lives. Some cultures also foster aggression or passivity more highly than assertiveness. But a single aggressive person can undermine an entire team, making everyone feel unsafe and vulnerable; and a single passive person can jeopardize an entire project by not speaking up.

Some people do not want to change and may have personal issues that prevent them from changing; you can control your reaction to their choice but not the choice itself. Team development can only go so far. For yourself and others in your team, if the situation seems beyond your ability to handle, consider outside help sooner rather than later.

How to Foster Assertiveness

Among the benefits of assertiveness at work are better communication, better decisions (since more options are offered), and more job satisfaction, as few people actually enjoy being ignored or shouted at. To foster assertiveness in yourself and your team:

• Keep in mind that any outside assessment can be deceiving. Aggressive people may consider themselves assertive; passive people may consider themselves merely polite. 
• Encourage “I” statements rather than demands. Consider the difference between “you need to focus” and “I would appreciate your full attention on this.”
• Support the positive “no,” which is essential for prioritization. Every team member has the right to say, “I cannot do that now but will get to it later.”
• Support the definite “no” when you can. Learn to distinguish between boundary setting and stonewalling.
• De-escalate emotional discussion, especially during crisis management or conflict.
• Gather and provide information about roles, goals, and mission. You cannot expect assertive behavior from yourself or others if you do not understand your goals or how you are supposed to reach them.

How to Deal with Aggressive People

You can call upon your own personal resources and upon organizational resources in dealing the aggressive people. Responses include:

• Stressing respect for and between team members, including by and for yourself, and setting clear guidelines.
• Listening, giving the person time to vent, without responding with either fear or hostility. You can say, “I understand that you are very upset and I’m sorry you feel like this.”
• Providing space and time for the person to calm down. You can say, “We’ll pick this up when you are calmer.”
• Meeting privately with the aggressive person to discuss the impact of aggressive behavior, possible causes, and ways to mitigate it. Your goal is to promote self-awareness.
• Checking regularly to make sure the aggressive behavior is decreasing and to support the aggressor in efforts to control the behavior.
• Involving Human Resources, which is particularly important with physical aggression and sexual aggression.

How to Deal with Passive People

Passive people may need more support than aggressive people and may be even less likely to change. Responses to passive people should include:

• Refraining from assuming “passive” means “passive aggressive.” Some people are just quieter and more withdrawn.
• Communicating one-on-one rather than in a group. While passive people should certainly not be excluded from meetings, they may be more likely to offer their opinion privately.
• Paying attention to body language. Individuals who are passive in speech may be quite revealing in body language. Encourage communication. You might say, “You look unhappy with this decision. Do you want to explain why it might be the wrong decision?”
• Offering opportunities for leadership, which may help to develop assertiveness and may also provide a learning experience for the team when a person they consider passive thrives in a new role.
• Checking regularly to make sure the passive person is coping and to support efforts to speak up or to demonstrate leadership.