Did you know that Vienna is farther east than both Prague and Zagreb? Or that Slovenia shares a border with Italy?
The residents of the Czech Republic, Croatia and Slovenia certainly do, and many of them would be more than happy to give you a friendly reminder if they ever heard you saying that their home country is part of something called “Eastern Europe”.
You see, it actually turns out that the term isn’t that popular at all in many of the places that a lot of us (including this writer) have been calling "Eastern Europe" for a long time.