Every gaijin who decides to put down more permanent roots in Japan needs to strike a balance with his surroundings. Some, such as ESL teacher types who naturally speak English in their day jobs, or others who don't plan on spending more than a year or so here, might reasonably be content with learning only enough Japanese to get around town and make friends. Other newcomers to the country might embrace the language more formally, perhaps setting using the Japanese Language Proficiency Test held in December as a goal to help motivate themselves. Some foreigners get into life here so much that they "lose their gaijinity" as it were, like an American friend of mine who reads a Japanese newspaper every morning and files his own Japanese taxes even though he has a perfectly good J-wife who could do it for him. Sometimes it can go in the opposite direction, like another friend of mine who's a full professor at a university in Kyushu, yet he actively avoids using perfect polite Japanese with the other teachers to maintain a "comfort buffer" of lowered expectations around him. Personally, I am happy being an American expat, able to speak the language and interact with anyone I need to, but always being "me" at the end of the day.
This American guy was made the head of his volunteer fire department. Congratulations, dude!