Haha, see, that's why I'm starting in small doses. I went for ten days, and fell in love with it (granted, that was a guided tour with hotels and everything already set up for us, etc. etc.). Now I'm going back again as a study-abroad student (hopefully) for a year, to test if I could actually enjoy living there for an extended amount of time. Once the glamour of Japan wears off and it just becomes "where I live", will even the love of Japanese culture be strong enough to overcome my desire, if I have one, to go back to the American style of living? Granted, my situation is pretty crappy right now (though I say that as a teenager stuck in a dorm room, I realize it could be much, much worse) in comparison to how it was back at home, but we'll see how it goes.
I understand where you're coming from, though. A pet peeve of mine is seeing all these people who claim they want to do the JET programme and become English teachers in Japan, and they don't speak a word of Japanese. I, for one, cannot understand how people would want to live in a country for three years or so as a teacher when they can't even communicate with their neighbours, or the clerks at the convenience stores. It doesn't make sense to me. Plus, I don't think some of these people really realize just how hard being a teacher actually is--I think they should try learning the language first, being a teacher in America where everyone understands them, THEN attempting something like JET. I think Americans tend to have a common mindset that no matter where they go, people will mold to accommodate THEIR needs, speak English to help them, and that living in Japan will be just like living in America, only with more wooden houses and sushi.
Everyone's experiences are different, though.
I can only wait and see how mine turn out.