Another sobering thought is that basically all memory of our existence will be lost within 3 or 4 generations of our death.
I ponder this every now and then. The author of Ecclesiastes said it best:
5
For the living are conscious that they will die; but as for the dead, they are conscious of nothing at all, neither do they anymore have wages, because the remembrance of them has been forgotten.
6 Also, their love and their hate and their jealousy have already perished, and they have no portion anymore to time indefinite in anything that has to be done under the sun.
Don't think about these verses as a JW proof text. Think about them as the words of an agnostic, or even an atheist. I'm convinced the part at the end about "fearing God and keeping his commandments" was added later in order to make the book compatible with belief in God. If you read from the start without preconceived notions, it seems clear that the author believes this life is all there is--and he's pondering his own mortality and the mortality of the countless millions who came before him.