When your spouse, for example, gets angry and ends up shouting and berating you, what's the consequence? Most people respond to aggression in two standard ways:

• They get aggressive back. They shout back, they point out the other person's mistakes, dredge up past wrongs, etc. Unfortunately, this only justifies the other person's anger in their mind and reinforces it and the aggression-making it more likely to happen in the future.
• They ignore it or give in. Because we're afraid of future or increased anger and aggression, we don't establish clear lines about what we will and won't tolerate when it comes to aggression. And even if we do, we don't enforce them. Instead, we give in, tolerate, sometimes even take responsibility for other people's aggressions-all in an understandable attempt to keep the peace. The problem is, this too ends up reinforcing the aggression, making it more likely to happen in the long-term because the other person learns that it's okay and that they can get away with it.