Vivekachudamani 12

samyagvicaratah siddha rajjutattvavadhara | 
bhrantoditamahasarpabhaya duhkhavinasini 
 (Vivekachudamani 12) 

The fear and sorrow created by the delusory serpent in the rope can be ended only after fully ascertaining the truth of the rope through steady and balanced thinking. 

Due to your ignorance. We are in suffering. We don't want to die. Death is there. We don't want to be diseased. The disease is there. We don't want to become old. The old age is there. So we don't..., so many things we don't want, but they are forced upon us. And any sane man will admit that these are sufferings. But if you are accustomed to these sufferings so you say, "It is all right," that is a different thing. But naturally, any sane man, he won't like to be diseased. He won't like to be old. He won't like to die. Because if there is war, there will be death. So people are afraid. They're making agitation, "There should be no war." So don't you... Do you think that death is a very pleasurable thing? 

So suffering's there. You have to take the version from realized souls, from, I mean to say, authorities that this... Just like in the Bhagavad-gita it is said that duhkhalayam asasvatam: [Bg. 8.15] "This place is full of miseries." So one has to realize it. Unless we understand that this place is miserable, there is no question of how to get out of it. 

A person who does not develop this miserable condition of this world, he is not fully developed. Just like the animals