There are many types of emotions inside a human being. Like happiness, contentment, love, hatred, anger and forgiveness, we can feel all these. We express our different feelings on different events. But out of all these two feelings are such, which can be called pure. One is anger and the other is sadness. These are two such emotions, which are very difficult to imitate. It goes so far as to say that in anger, a person sometimes speaks the truth, which a person always keeps hidden. Watch the special analysis on anger in DNA.