The "circle-of-life" of man, relates to the divine truth , that all we experience, are due to the will of man, but are influenced, by the will of God (Universal Consciousness).
Hence, essentially, there is no good or bad experiences, rather, it just is, as part of our destiny unfolding, by the will of God.
This is so, since contrary to popular belief, we soley exist in the consciousness of God, as spiritual beings, having a human experience, performing as an instrument of God, in a non-subjective reality.
This is analogous to a man first getting on a rollercoaster ride, which we call birth. Then whose movement in life is guided by tracks he's not in control of, traveling up, down, and around, which we call life.
Then the rollercoaster ride stops and he gets off, which we call death, more precisely "passing on."
Yet another perspective, is that we are all actors on a stage, we call Earth; where we as actors, are guided by a script, we call our destiny; with God as the director leading the way.
Thus, in both analogies, rightful thinking simply involves enjoying traveling down the river of life fearlessly, and with gratitude, for there is nothing that can harm us, since we are blessed as chosen spiritual beings to have a human experience, performing as an instrument of God.
Such is the "circle-of-life" of man. And so it is.