Many people see anger as a negative emotion. Yet, anger can be an energizing and healthy emotion, if dealt with in an appropriate manner. For many people, especially women, anger is a difficult emotion to express.
Society teaches women to be nice, compliant, and generally happy.
Because of this, many women do not think it is acceptable for them to be angry. Societal expectations for men are somewhat different. Men are encouraged to express anger, sometimes in a physical, or aggressive manner. Of course, this does not mean that all men express anger this way. Sometimes people have such difficulty expressing anger, that they ignore their body's way of reacting to anger.