Actually I disagree with that. Compared to Chinese, Japanese might seem that way. There are many aspects of Japanese where subtle differences in intonation can convey totally different meanings. Aside from this, tones of voice, gestures and body language also play a role in Japanese. In many ways, it's much more important because it is a language which is extremely vague by its nature, so people are often left struggling to understand the real meaning of what is being said (even for native speakers sometimes!)

But I see you've listed Japanese as one of your languages in your profile, so I am guessing that it is at least at a level where you know something about the subject.

Probably the biggest example (for me) where intonation is used in Japanese is the same as in English - going "up" at the end of a sentence to indicate a question (omitting "ka" in casual speech).

Don't confuse rudeness or poor service with some kind of linguistic characteristic. Acceptably polite? Not in my book!