I would really like a book that documented all the potentially offensive "collisions" in the ways that different English speakers define words. For example, the book would point out the fact that "root" means something in Australia, and "fag" something in the UK, that is very different than what they mean in the US.
If I had such a book, I would travel the world making each mistake loudly and conspicuously and then blaming it on ignorance of cultural differences. Such cultural clashes can hardly be considered real transgressions and be held against anyone who convincingly acts as if it was a mistake. It would both be educational for everyone involved -- and we'd all be a little happier afterward.
