Sometimes the simplest things can be the most fascinating. The phases of the moon are regular enough, changing from night to night in an endless cycle month to month. But if you consider the scale of the thing; the length of the lines of shadow; the whole thing becomes breathtaking.
The careful observer of the smaller details of the lunar orbit will find little hidden wonders, adding to the wonderment. Have you ever noticed that the crescent moon in summer is shaped like the letter C (frontwards when waxing, backwards when waning)? But in winter, the shape is more like a slightly tilted letter U. This is because the path of the summer moon is at a smaller angle to the horizon whereas the winter moon takes a more direct route across the sky. As the autumn season advances, you can see more and more that the crescent moon will take on its “holding water” shape.