What is it about death that makes us fear it so? How it will happen, the pain we may endure prior to death? The uncertainty of what becomes of us after death? The possibility that are soul may be bound for damnation? Perhaps the scariest thought is that of our souls ceasing to exist.
Whatever the reason, the majority of people do fear death to some degree. Following a religion may ease fears as we are promised rewards after death for good behaviors in life. We may enter into heaven, or become reincarnated if we abide by what our religious leaders preach. However this doesn't clear up all the uncertainty. Many of us still have doubts. The main reason being that we have no proof there is a life after death of any sort.
Some have claimed to have had a near death experience, or out of body experience during a trauma. The most popular of these tales are those that claim to have seen a bright light that appeared warm and welcoming. Some may even say they've seen the silhouettes of people, possibly their loved ones who have died before them. Are these recounts real or was it the person's imagination?
There are arguments against every theory, including that there is no tangible proof supporting any idea. This may be the main reason for everyone's uncertainty. This, perhaps, is the main reason we fear death. The fear of the unknown. Perhaps we will go to heaven, or be reincarnated. Or perhaps we are destined some place worse, purgatory.
The only theory that appears to have the most proof is that our souls and conscious will cease to exist after this life. Arguments against this theory are those of religious persuasion, none of which can be backed up with real proof. One could argue that since we have not been shown what happens after death, that it must be true that we all cease to exist. The idea doesn't need proof to be believed. That is the nagging fear in the back of everyone's mind. That possibly this is the truth and what we are told about heaven or some form of life after death is just to quell our fears.
One could almost theorize that perhaps we are not meant to know the truth of the after life. If we were to be shown proof that life after death existed, we would no longer fear death, therefor would no longer hold life valuable. We would not worry so much about our loved ones if they were sick or in danger. We would have less fear about losing them. We wouldn't view our own lives as valuable, and would take larger risks. We would not learn empathy.
It very well could be our fear of death that keeps us living our lives the way we do, the way we were meant to.