NPR had a podcast episode (Planet Money maybe?) about how the EU was supposed to make it easier for firms to hire cross border and employees to move around. The idea was to be more like the United States.
Apparently, this didn't quite work out due to both language and cultural differences
Then, one of the guests says:
"Yes, there were some challenges. In fact, we ended up getting books with titles like: 'How to manage Spaniards if you are a German'"