In the Accounting field there is something called The Principle of Continuity: when stating financial information, one should assume that the business will not be interrupted. In other words, we should assume that the business will go on forever. As humans, we tend to use the same principle.

For instance I take my existence for granted. I have always been here and I will be here forever. We do not think of a lifespan, nor do we consider the two defined points of our life: birth and death.

I guess we should consider that as humans, at one point we will cease to exist. One should make the best out of his/her life.