Sadness is a situation when the emotions of people realize that they do not have a way out. Sadness is one and most significant of the few negative emotions that is sung by poets and prose writers. Also, there is something intimate and tender that can be seen in the mild sadness.
Sadness can be useful sometimes. It lets people to think about their sense of life, about the chosen path. Sometimes when a person is sad he or she can meet another person who radically changes his life. Additionally, sadness is a muse for poets, artists and prose writers who later created masterpieces.
Sadness can motivate people to take action or force a person to improve what is the cause of sadness.
Also, sadness leads to understand that someone can be even worse. Understanding this kind of situation gives rise to sympathy and a flood of tenderness.
Sadness usually causes tears that ease the state of mind.