The moon is the largest object in the sky and it is no wonder it has long been a part of human ritual. Also the moon goes through many phases, from almost non-existent to a full moon where night is almost turned into day. On a full moon it is easy to see craters and other features of the moon with just the naked eye. All these things make it evitable that the moon would be woven into human spirituality. Moonspun is the general term for the various mythologies that have been spun around the moon.
Of course there are practical reasons to take an interest in the phases of the moon. The moon has a direct influence on the tides. The combination of tide and the brightness of the moon are thought to be a major factor in whether fishermen will be successful or not. Also early hunters would greatly benefit from a full moon when hunting at night. Indeed for early man a dark night with no moon would have been quite scary, especially when predators were not as handicapped.
However these practical reasons do not explain the extent of moonspun mythologies. Many ancient peoples have built elaborate temples and structures that seem to track the movement of the moon. The Maya tribes of Mexico and South America were known to build grain stores that aligned with the axis of the moon through the sky. Also these grain stores seemed to align with particular lunar events such as full moons in early spring and midsummer. This might indicate that the planting of grains occurred at times of the full moon. Also it appears that certain animals were only hunted on certain phases of the moon, whether this was due to the amount of light at night or some deeper spiritual meaning is not known.
Even for modern man the moon has special meaning. The ultimate prize in the space race was to land a man on the moon. Sure the moon is the closest celestial body in the sky, but it is also an object that every human can see with the naked eye and feels close to.
So whether for practical or spiritual reasons humans are fascinated by the moon, we are all moonspun.