As you can see from the other write-ups here, there is a lot to say about The Moon. It is only right that scientists, poets, historians and mystics all have an intimate understanding of it, as it is, in a sense, the property of us all, even if it is just as an enigma to wonder upon.
There is one basic understanding of the moon that I have never yet seen written down, and am continually surprised at how few people know it, even to the the extent that a popular piece of moon phase software got it wrong, despite the arcane detail it contained. The observation is simple, it is one that our forebears would all have known immediately, almost instinctively, perhaps we have lost it because we habitually gain our knowledge without looking at the subject itself, that and the fact that the moon no longer plays a role in ordering our schedules as it once did*.
The simple observation is this:
The waxing moon has its convex curve to the right hand side (the chunk is missing from the left hand side), till it grows full round, then as it wanes the curve is on the left (the chunk missing from the right), till it becomes new (at its darkest). In other words only the waning moon is a C.
Not very important maybe? But next time you see the moon you will be able to tell if the nights are getting brighter or duller, something that up until living memory any small child would have known. Try asking your friends if they know the difference.
Thanks to DonJaime who has pointed out that in the southern hemisphere it's the other way round. Having never been, I cannot confirm this, I would be grateful if anybody else could confirm it as so.
*Before streetlights and automobiles, journeys were planned to make the most of the full moon to light the way, the great historic balls and other great gatherings were scheduled to correspond with the full moon to minimise the risk to those invited. During the new moon social calendars for large groups were restricted to the daytime, the roads would have been comparatively empty at night except for those who did not have to travel far, or who had no alternative.
source
The Birth of the Modern: Paul M. Johnson