Mortality. The mere mention of the word can cause those to turn away, change the subject, or become fearful. Life is the mother of death. That which is born, must die someday. All followers of the Dao know that death is natural. In Julius Caesar, Shakespeare wrote;
Cowards die many times before their deaths;
The valiant never taste of death but once.
Of all the wonders that I yet have heard,
It seems to me most strange that men should fear;
Seeing that death, a necessary end,
Will come when it will come.