What is your opinion of Carl Jung's theory of "collective unconscious"?

Carl Jung's theory of the "collective unconscious" operates on a fairly simple base principle. Namely, he posits there are impulses and memories that are common to all mankind regardless of whether or not a specific fear has been realized in an individual's life.
Jung labels these ancestral impulses and images "archetypes" and hypothesizes that they are innate across humanity and not dependent on personal experience. (This is the dividing line between the "collective unconscious" and the "personal unconscious," in which impulses are informed directly from events an individual experiences.)
The study of human mythology afforded, in Jung's view, a glimpse of the collective unconscious at work. His archetypes often take a central role in mythology, emboldening his opinion that the religions and spiritual behaviors of human beings were projections of a collective unconscious.
Ultimately, the theory is nearly impossible to prove given the supposed nature of the collective unconscious coupled with our current understanding of human brain structure.
Further Reading:
https://www.britannica.com/topic/collective-unconscious

What you feel about Carl Jung's theory of "collective unconscious" is up to you. To arrive at your opinion, you should think about what Jung meant by the "collective unconscious." He believed, that underneath the conscious mind and our personal conscious, lay a collective unconscious, in which we share common archetypes and instincts, many of them primitive in nature. One of these common archetypes included the shadow, or the animal side, of our personality that governs our creative and destructive forces.
One aspect of the collective unconscious that you might want to think about is that people tend to share similar types of dreams and fears. For example, snakes and shadows often show up in people's dreams, and people are afraid of these images, even if they have not experienced them directly. Very few people in the developed world have had an encounter with a poisonous snake, but they remain deathly afraid of even the image of a snake. Jung would argue that our fear is a remnant of the fear of our ancestors in the primitive past. In addition, while some of Jung's ideas have been dismissed as belonging more to the world of myth than to the field of psychology, some of his ideas have gained widespread traction in psychology and in our understanding of ourselves and our personalities. For example, his ideas of extroversion (the turning of attention outward) and introversion (the turning of attention inward) have resulted in tools such as the Myers-Briggs Personality Inventory (MBTI) that allows people to understand the way that they characteristically work, based on these factors, as well as other factors. Therefore, Jungian thought has some applicability to today's world.