Tantrum is used as a way to attract attention to himself. When you can not convey thoughts to the opponent with words, a person starts a tantrum. Cries, tears (sometimes even fight), are designed to turn the tide in their favor. It is also a way to discourage the interlocutor, to switch his attention from the main to the secondary. Distracted by the display of emotions, a person is able to change his point of view under such psychological pressure.
Rapid display of emotions can influence the psyche of the other person. Not everyone can safely withstand the hysterical manifestations. Many people are willing to accept anything as long as it does not hear. In addition, communication with the hysterical man takes a lot of energy. He becomes a kind of psychological vampire who feeds on the energy of his interlocutors. Usually people try to reduce the time of interaction with such people to the necessary minimum. They feel that they can not cope with the impact, but can not resist this. However, this should be done if you want to maintain their position.
To avoid pressure from such people, with manifestations of hysteria try to stay calm. Do not show that you is somehow annoying. Remain indifferent to the hysteria of the interlocutor. You can offer him water and call an ambulance. Having seen several times that his hysterical manifestations do not lead to the desired result, your opponent will stop using hysteria as a means to manipulate your emotions.