Postby seanolan » April 15th, 2007 11:18 pm
Keep in mind their position. Your boss, for instance, might use casual to you, but if you respond in kind, he will be taken aback, unless it were at a drunken enkai or some such. Japanese people NEVER forget relative social status, EVER. However, if someone of the same social standing (co-worker, fellow student, etc) uses casual to you, using polite can take them aback as well, subtly indicating that you do not consider the relationship to be that close.
As foreigners, they do take our ignorance into consideration generally, but their gut reaction will be there, even if their mind tells them to ignore your social gaffe.
Generally speaking, those higher than you should ALWAYS be addressed by polite forms, those equal to you should be addressed as they address you, and those lower than you can be addressed with either form, but realize that if you are too polite to someone of a lower social standing, they may either think you are mocking them or may try to outdo you on politeness in their language, making it REALLY tough to understand them when they start using humble forms, etc.
Sean