The Japanese have two words: "uchi" meaning inside and "soto" meaning outside. Uchi refers to their close friends, the people in their inner circle. Soto refers to anyone who is outside that circle. And how they relate and communicate to the two are drastically different. To the soto, they are still polite and they might be outgoing, on the surface, but they will keep them far away, until they are considered considerate and trustworthy enough to slip their way into the uchi category. Once you are uchi, the Japanese version of friendship is entire universes beyond the average American friendship! Uchi friends are for life. Uchi friends represent a sacred duty. A Japanese friend, who has become an uchi friend, is the one who will come to your aid, in your time of need, when all your western "friends" have turned their back and walked away.
Otaku (おた) is also a formal way of saying "you". た means "house", and with the honorific お, it literally means "your honorable house", implying that you are less of a person and more of a place, fixed in space and contained under a roof. Makes sense that the stereotype of the modern otaku is a shut-in, an obsessed loner and social isolate who rarely leaves his house.