@s1m0n4 That's the question. In their culture, age is very important. Even a month of difference can be a big thing depending on how and where it is applied.
For example, when they're meeting for the first time, they ask each other's age, which is considered rude in other countries. A lot of things and traditions are dependent on knowing each other's age.
Here in the Philippines, while we have something similar… at least within the family, like cousins, it is generally expected we call someone at least a month older than us as “ate” (big sis) or “kuya” (big bro), and give deference and respect. It's a good thing it's not in our tradition to ask each other's age, otherwise, we'll have to give deference and respect to everyone outside of the family as well. ^_^;; (But we don't consider asking each other's age as rude. And if we do, we can discuss if we have to give deference, use honorifics, or not.)
I don't know. I guess it's an Asian thing. Deference, honorifics, respect, are huge here. But, I guess I'm happy we're not as strict as the Koreans… I'm going to have a headache of all the things to be careful about. ^_^;;