A recent theory says that while getting angry or crying, one is secretly manipulating others to behave in the way that he/she wants.

Our emotional tools have developed to influence others into cooperating with us. It has also been observed that anger is associated to conflicts as well as cooperation.

If someone gives us something to help us avoid some kind of penalty, we do not feel obliged whereas if the same amount was given as a favor by himself undertaking some loss, then we appreciate it.

It has been observed that we are grateful not when someone helps us but when we get something more than we what we had expected. This stimulates one to plan his or her reaction.

But there are many who don't approve it and there are also some who deny it on the ground that there is no strong evidence to prove whether anger consists in some kind of compromise or it is a just-so story with no specific reasoning behind it.