It is very fascinating. I'd recommend "Watching the English" to non-English people, too, as an insight into how differently different nationalities do... well, pretty much everything. There are several Amazon reviews written by non-English people who have lived here for a few years, and are saying, "Wow! At least it all makes sense!" They'd struggled for years to make friends, or to speak to people without unwittingly giving offense, and until they read the book didn't understand what they were doing wrong.

(Which does make us sound like a real, forbidding bunch of psychos, doesn't it?)