In Japanese, there's a whole subset of polite language called keigo which can be quite a challenge for foreigners to learn, since we don't have anything like "exalting" and "humble" verb forms for raising up the person you're speaking to while lowering yourself in comparison to them. I recently had instance to write an email to a certain company in Japanese, and to make sure I hadn't made any serious mistakes -- I'm sure there's nothing more amusing to Japanese people than foreigners screwing up their language -- I asked Yasu to check the email. He made quite a few changes, making the overall tone of the letter more formal and catching some of the little things I'd missed, but before I sent it out, I found myself replacing some of the extremely polite and accurate language he'd added with what I'd originally written. I think that gaijin have a certain reputation as being passionate and emotional, and I wanted to preserve some of that spirit in my email, even if it meant the Japanese I was writing wasn't as "proper" as it should have been. One important part of learning this strange and wonderful language is developing a personal balance between the various aspects of it.
The use of polite language between human beings is an interesting side of Japan.