In a lot of Asian languages (I know Korean and Chinese for sure), there are different words from older sister, younger sister, older brother, and younger brother. I enjoy thinking about language and culture. The absence or presence of a particular word within a language says a lot about a culture.
So, learning about a culture that necessitates words for older sibling and younger sibling has lead me to think more about these relationships that I probably would have normally. I'd say sociologically and psychologically, this idea of pecking order within a family has a lot to do with typical personality types and development. I think it's interesting that Chinese identifies with this idea with specifity in a way that English does not.
Coming from a big family, sibling relationships been a pretty important aspect of my foundation. Growing up I was always called "the baby" and then at age six, Jim came along and my title was prefixed – "the first baby." And with this, I became both a 姐姐, 妹妹 (a jie jie and a mei mei). I've learned a lot from the examples of my three older siblings (my two 姐姐 and one 哥哥). And now I have a 哥哥-in law. I've learned a lot from him, too (starting with how to take an engine out of a car). And my one 弟弟 is pretty awesome, too. He's taught me a lot, too. They've been really good examples.
Great people. Love 'em. Miss 'em.