Our moon is comprised mostly of Earth mantle material, the result of a collision billions of years ago. We are fortunate to have a relatively large satellite but there is nothing particularly "capricious" about its size and location. At one time is was much closer to Earth and had a faster rotation; today, it is much further away (and continues to recede by 1.5" per year) and is rotationally locked to its revolution (the lunar month). We aren't talking crystal spheres here. Our planetary system has a messy past. Life has emerged and evolved partly because of this...and partly in spite of it. The story will be different...but kind of the same...when we find life on other planets.