Question: Is there a single greatest fear that has determined the course of your life?
Answer: I think at the end of the day – since the individual existence of our self is our greatest treasure – our fear of death dominates us, whether we admit it, sense it consciously, or not.
This fear of an irrevocable “end”, the fear of incomprehensible darkness beyond physical death prompted most of our philosophies, religious ideas, systems, our craving to improve technology, medicine, etc.
But there is a point where this fear of death awakens an even greater fear: “Will I ever reveal, find the true meaning of my life, do I have enough time to find my Human purpose, to justify my Human existence?!”
From then on this fear determines our life, success us towards that purpose.