Why being old and die (mortal) are so terrifiying to some people?

Question:

Why being old and die (mortal) are so terrifiying to some people?

Best Answer - Chosen by Asker: People are afraid of things they neither understand nor have any experience with. In other words, if they haven't been there and don't know what's going to happen, they have a greater chance of being afraid of it.

People who have a strong faith in the afterlife do not usually experience this terror, since they believe they know what lies on the other side. If you know what is coming, you aren't afraid of it.