On a slightly higher level of basic manners is learning the language of one's new country when a long-term stay is the objective.
Oh, Deep Funk, you have me "banged to rights" there. Caught in the act. Shamed and named (except you didn't know it was me!). I have lived here for ten years, and I still do not speak the local language.
That is not something that happened by intention at all, quite the opposite. It is a combination of the fact that it is so easy to get by here in English, and a mental block that I could not demolish aged ten, let alone fifty years later. It's easy to get by, but life would be so much better if I were not linguistically challenged.