I'm not just talking about the ability to disagree politely. That's important, but in business the challenges are greater than that. Buying, selling, competing, cooperating and managing require close interaction. Relationships have to be built. Trust must be developed. It can be difficult, and the more deeply you are involved (like when establishing an operation overseas), the more difficult it gets.
To operate in this kind of environment, a certain perspective is required - what might be called a "global mindset." To have a global mindset is to have the perspective, imagination and empathy to understand the other guy's point of view, the conviction to stand by your point of view when you must, and the flexibility and creativity to find new approaches and common ground when necessary and possible.