Kaoru Hino, share your thought not here, but in the History & Traditions.

One of the examples: when you came here, you always think everyone can speak at least English (at least around Tokyo area), but you just have to ask:
-ちょっと、英語分かりますか。
When I answer your question above in English, "Yes" or "No", then someone else points out, "I don't know why all Japanese always answer my questions in English, even though I ask them in Nihongo".