Being a teacher, or sensei, in Japan is a big deal. In the States, we talk a good game that teachers are angels sent down from heaven to learn our kids to read good. But secretly a lot of us, most maybe, just think teachers are people who were too dumb to get real jobs. In Japan it's different. The pay is about the same but the Japanese have a deep-seeded respect for teachers.
This respect is coded in the language. The word for teacher is sensei, which literally means "born before." That is, the word for teacher essentially means elder. Nowhere in the word for teacher is the word for teach, oshieru. Thus, teachers implicitly deserve the same respect as one's elders. In a country that reveres its elders as superiors by virtue of age, and worships its ancestors, teachers recieve the same respect as older people, regardless of their age. It's like being an honorary elder.
A side note -- the Japanese find adressing someone as "you" too direct and therefore disrespectful. This leads to a sort of funny conversation style in which people speak about each other in the third person. If you wanted to ask me, "Do you like fish?" you would ask, "Does John-san like fish?" That essentially means, "Does the honorable John like fish?" or, "Does Mr. John like fish?" Being a teacher however, people refer to me as sensei or John-sensei.
I often go to a hole-in-the-wall yakisoba restaurant in my town. It's run by a small lady who I can only assume is 150 years old. She's one of the few Japanese people I've seen that looks older than 20, so I can only assume she's in triple digits. However, when I come in to get my food, she addresses me as sensei. Now this woman is most definitely my elder, but apparently my clout as a teacher trumps age in this small town.
I thought it might have been because it was a small town and they essentially need me -- I'm the only JET Programme teacher in the town. However, I've been in situations even in Tokyo, in which, people begin to respect me more and refer to me as sensei once they realize I am a teacher.
I don't know how I feel about the unquestioning respect. It's nice to get it, but how do they know I don't suck? I've encountered plenty of god-awful teachers who deserve less respect than your average person. That said, I've also encountered plenty of old people who deserve little to no respect. For a Westerner, even one who has studied Japanese language and culture, living the Confucian hierarchy can feel a bit odd.