Thus, forgiveness is a key principle of Christian living. People tend to be like pressure cookers. As offenses received from others are stuffed inside, the pressure inside increases. In pressure cookers, steam is released periodically by a pressure control that makes a jiggling sound as it lifts and returns to its seat. But if the pressure control does not work, the steam pressure will continue to increase until the pressure plug melts, and then the steam will be released in one big burst.
Some people function like the pressure control.
With each offense they receive, some of their anger comes out in words or actions that are anything but pleasant and edifying. Others function like the pressure plug. They hold the pressure of their anger inside for a while, and then blow up like a volcano. If it really helped, ventilating feelings would be a reasonable way to handle anger. But ventilating feelings has one very serious drawback.