Person needs time to get rid of inner tension. And this should not remain calm at all costs, not to hide emotions, but rather to give them a way out. Of course, within acceptable limits. In other words, one has to know when to be angry, not to go to extremes.
For example, the behavior of a colleague irritates you, causes discomfort. And more and more, so that you have to see it can not. But you are considerate and accommodating people, so keep your emotions under control and continue to suffer further. Sooner or later, the case is over, or a heart attack or scandal (well, if not physical abuse). It was only two choices: either to completely stop all contact with this person, it is not always possible, or openly talk with him. Well, to explain. Even in a raised voice, it is still better than hoard dull irritation. It is quite possible in the end it turned out, he did not mean to offend you, do not even suspect that some of his words or deeds cause such a painful reaction. You just do not understand each other.
There are plenty of safe ways to get angry, relieve tension. Starting with the notorious "sheet of anger." Feel that is about to explode - Take this sheet, crumple and toss into the wall. Or, for example, broken pencil. A good way - Remove the carpet on the street and from the heart will beat, beating the dust. Of course, nothing prevents you to submit your rug in place detractors. And in some Japanese corporations have gone further: in the rest rooms are mannequins depicting the heads. And everyone can thrash them with impunity. Remember: people - not machines. Them from time to time have to be discharged.