Do not think about your death
What we think about our death and implications of that on our decision by Sheldon Solomon in The anatomy of human destructiveness.
He is known for something called Terror Management Theory which can be described as:
It looks at what researchers claim to be the implicit emotional reactions of people when confronted with the psychological terror of knowing we will eventually die (it is widely believed that our awareness of mortality is a trait that is unique to humans).
This wiki page is defenatly worth a reading.