When we observe people around, we find that we can categorise them based on some common features- esp their behavior which depends completely on their nature. So, basically we categorise the different natures. And I think, that's how the different states, countries or the worlds that we see around us have been formed. For e.g., If you observe the thought process and nature of the Americans, you find a commonality in most of them- that is, when you say you are an American, we get an idea of what sort of a person you 'could' be- like- independent-living, fun-loving type. When you say you are an Asian, people generally are subtle and obliging type. These are just examples, but in general, depending on the kind of nature you have, you create that kind of an environment around you. When you say you belong to Karnataka, Tamil Nadu, North India etc., we again find a similar trend- "similar patterns of nature". We immediately form an idea in our mind about what sort of a person you could be.
Also, an interesting thing is that- people who believe in astrology assume that planets and their positions have an influence on their lives and many can even predict future direction. I think your nature has a direct connection to the time in which you were born and the associated planetary positions during that time or atleast, we can try to link it up. Given that you are born with a certain nature and some inherent tendencies, your life or the likely path you might tread in your life are mostly dictated by those tendencies or patterns. People can generally get to know what kind of a person and what kind of a life you will 'tend' to lead if they know your tendencies. But people cannot read your patterns unless they know how to read your mind. So, instead they can read planets!
Now, the planets also follow some trend- they probably go through some changes in positions based on which the different astrological signs are created. If there was a way to link up the tendencies (which in turn lead to some events in life) and the planetary movements, man can predict consequences in life through planets and I think that's how astrology should have been born, although I dont know if people ever look at it from that point of view. So, when he knows your bith star or horoscope, he can predict what's the likely path you can tread. Now that's a great thing, but he attributes all this to the poor planets- and says that planetary positions cause such and such a thing in life. That's when I would disagree. If your nature is under your total control, who cares for the planets. If you are capable of changing your nature to adapt yourself to happenings in your life, why care for planetary positions? So, basically I am trying to say that- astrology can also be seen as linked to your "patterns" and depending on the different patterns, you find people getting categorised in astrology under different astrological signs.
Again, here, you will find commonality between people under the same sign. And people say- If you are born in December- you are likely to be acting in a particular way, if you are born in July- in a different manner etc., So, we categorise people with certain nature into certain signs. This again goes back to our first example of how we categorised people in different countries based on their nature.
The same can be observed with respect to animals- the ones having majestic and dominating nature being born as tigers/lions, the ones with a tender nature as a sheep or a deer etc., So everywhere there is this categorisation- some boundaries within which you have defined your nature.
I would just reword the common statements that people make. Instead of saying- you are the way you are, because you are an Indian or a Cancerian born in a certain village, I would say- Because you are the way you are, you chose to be an Indian and a Cancerian in the village you are!
It is the same case with different professions. When we find a professional, we say that he has certain qualities because he is an MBA or a lawyer or a theatre artist etc., but I would say that because his nature already had those tendencies for those qualities, he could become an MBA or a lawyer or an artist.
It is really amazing the way the countries and states and castes and in general - the world has got demarcated based solely on "nature", on their "patterns".