The fear of death.

 Death. Why do we fear it if we've been in that unconscious state long before and in an infinite time before we have given birth. Why do we mourn when someone passes away, especially at a young age? Because we feel sadness over the loss of experiences that person could have experienced in their potentially long life time. Why do we then not mourn of the losses of experiences a new born could have had before birth? Since life is a physical manifestation of the human body of which they would have not had and therefore not had had the experience to go through it.

We fear death as it is uncertain. We as humans will always fear the unknown. The fact is, nobody knows what death feels like. Do we believe in life after death? (Existential nihilism) Do we believe that there is a soul or something that resembles it that carries past our physical bodies.

A better question rather: Is it important that we keep hope in life after death?

Albeit all the doubts we have in death, we still live our lives to the fullest. Because whether or not there is life after death, we still appreciate the intrinsic value of life. Therefore it only influences our perspective of the world. Say there were a soul. 

Someone who doesn't believe in life after death, it is easier for them to accept. It is merely the end of the road, the end of the river that is life. For someone who believes in life after death or rather a soul, there is a fear of the unknown, because you believe that there is something, you just don't know what.

2 types of people: Physicalist, duelist. Duelist believes that there is a soul. Physicalist believes living is just of a physical sense. Physicalist can accept death easier. Duelist struggle to quantify what happens after death. Religious people (Duelist) who head to religion for assurance, for non religious people they live in fear of the unknown.