Why is God? Why is Religion?

There is an ongoing debate about the existence of God. Is there a God? And if so, What or Who is God? Actually, there is no universal definition of God, so if one wants to believe in God, one can take whatever one actually believes and say that is God. Conversely, if one desires to be an atheist, one can define God in such a way that excludes God from whatever the atheist believes. However, I think the more important question is not whether or not God exists, but rather why is there God. Belief in one or more deities has existed in various civilizations, both sophisticated and primitive, no matter what extent of isolation, since prehistoric times. Why? Let us imagine a prehistoric person living in a time when language has begun, and people can now talk to each other about what has gone on in the past (history) and plan for the future. There are now stories of ancestors who no longer exist. Life is temporary, unpredictable, chaotic. Now people can begin to realize that their time of life is limited. The same can be said nowadays for small children who suddenly discover the same fact. It is frightening. One needs a way of making sense out of the temporary nature of existence, some permanence, some order out of chaos. So, the answer for early people was often a belief in the sun or the moon or some mythologic greater than human gods or eventually one almost abstract God. They all served the purpose of giving meaning to a seemingly otherwise meaningless existence.
Unfortunately, like any institutions, people eventually began to find secondary gains in religions. People believed their own religion to be "the true religion." People felt the need for others to believe in "the true religion" even if it meant killing or harming other people to force them to believe correctly. Religion often became entangled with government and politics. This misuse of religion is actually contrary to the original purpose of religion to give meaning to life, to make life more tolerable. I believe strongly in the separation of church and state. Although religion can have a negative effect on government by imposing the ideas of a particular religion on people who do not necessarily follow that religion, more importantly government can have a negative effect on religion, diluting its real purpose of giving meaning to life by involving it in pursuits unrelated to that purpose.