Why am I here? Why are humans self-aware? Why do we have the urge to create beauty, art and solidity; and to "leave something behind" for posterity?
By asking that question we find a need to create a reason for our existence and so we create deities, philosophies and religions. Then the inevitable wars, hatred and distrust appear, wreaking a different type of creativity on the planet. That of death, disease and hunger. An unintended legacy of destruction is created.
Did there need to be a reason? Humans evolved and die. The end.