The golden ratio, is present not just in mathematics, but may also be present within your own brain and body (at the atomic or subatomic level), what do you think it means? is this number evidence of a grand design, a massive freak coincidence or something else?

This is open to interpretation and one may fit the explanation to what they see fit. A possible explanation is that this is a "grand design", in which everything that meets the criteria for existence set by nature is encompassed. If this ratio is satisfied, the product is a good one.