We can come up with all sorts of reasons why something might be, but the bottom line is that sometimes it just
is and we may never know the true "why" of it. As humans, our understanding of the workings of the Universe (including math and numbers) is limited because our brains are limited. We can notice repetitions and patterns, but the why of it may be lost on us. Sometimes we just need to "get" that something is and move on.
For me three, seven, and thirteen are recurring numbers. I know of a lot of reasons why these are important numbers, but knowing that doesn't affect why they come up. I've long since given up trying to rationalize it and just "go with the flow".
