As I was thinking over various things last night, I realized that the reason why my Japanese has barely improved after a full year of living in Japan is mostly due to four characteristics/traits of mine:
1) I learn better through reading/writing than listening/speaking
2) I have an overdeveloped sense of responsibility to/for others
3) I have an underdeveloped sense of responsibility to myself
4) I'm lazy
The first is pretty obvious. Even though I'm surrounded by people who speak Japanese, because I'm not much of an auditory learner, I pick up relatively little from conversation alone; I need to study (i.e. read about or write things down) to really retain information.
And the reason why I haven't been studying Japanese is related to the other three characteristics. The overdeveloped sense of responsibility to/for others means that I am willing to expend a lot of energy on things that I feel will impact others. It's the reason I will stay up late making materials for classes, or will go to Kirita or the office after other school visits or on weekends (i.e. on my own time). If I feel that I am accountable to or have a responsibility to someone else, I will push myself to live up to (and hopefully exceed) expectations.
Conversely, I don't really feel much of a sense of responsibility for my own health, mental well-being, etc. So I often work late and skip dinner, or stay up late getting things done in spite of fatigue. It's a rather deadly combination, actually. The first two weeks or so after I came back from Canada, for example, I was at Kirita helping the students prepare for the speech contest until between 6:00 and 6:30pm. (If I had other school visits I was going to Kirita on my own time afterwards.) Then I would rush straight to either an eikaiwa, Japanese dance class, or taiko practice. I'd get home between 8:30 and 9:00pm and be too tired to bother eating dinner. But then I'd stay up late working on lesson planning or the junior high school newsletter or other work related stuff. (Japanese dance seems like a personal thing, but the main reason I joined is because I was told there has always been an ALT in Japanese dance, and the teacher is one of my student's mother, so I felt like I should join.)
So basically I put a lot of time/energy into things I feel are obligations/responsibilities at the expense of eating and sleeping properly and taking care of personal things. And since the level of Japanese I have right now is sufficient for teaching/getting along in life, improving my Japanese falls into the easily neglected category of "personal things" (i.e. a responsibility only to myself).
Throw in my final characteristic of laziness and you can see that when I actually do have free time, I'm too lazy to study and choose to do things like reading books/manga or watching TV series/movies instead.
Well, now I know why it's so difficult for me to study/improve in Japanese, but I have yet to figure out how to change things. Maybe I'll have time to figure something out next (school) term when it's not so busy. ^^;;