I recently came across a very interesting TED video addressing the differences between the American and British cultures on the specific aspect of politeness. I grew up in the Midwest of America, emigrated to Scotland, lived in England for a while as well, and have friends scattered all over the “British Empire” & Commonwealth; I now live in Switzerland (adding several “Germanic” mentalities to my experience in that process!). What the speaker (Lynne Murphy) observes makes a LOT of sense on both sides of the Puddle (Atlantic). I share it with you because as a writer I know that those subtle, unspoken, unwritten differences in the ways people interact with each other and show their masks, or as Lynne calls them “faces”, make or break the authenticity in writing both prose and dialogue. Click on the image below to watch the video; it’s 18 minutes long, so please watch it when you have time to focus! (By the way, the two cartoons below illustrate perfectly the difference between the “positive” face and the “negative” face.)
Stephanie Huesler 
Very interesting. Some of it I couldn’t catch even with the volume at 100%, but very interesting that I was able to hear.