[jxf]

> the countries there are more similar to each other than to other countries, so combining them is natural.

That seems like a very inaccurate generalization. If you think, say, Egypt is "similar to" Madagascar, Malawi, or Mozambique, that's difficult to agree with.

They're in rough geographic proximity, if that's what you meant. But downtown Manhattan and Ecuador are also the same distance apart and they're pretty different.

[ars]

I had a feeling someone would mention Egypt. But despite where it actually is Egypt is usually called Middle East, not Africa.

And you didn't reply about people combining Europe - to someone in Europe France and Germany could not be more different - to someone outside Europe they are more similar than they are different.

[jxf]

That's precisely my point -- that it's important not to succumb to our internal biases. Just because we think they're "mostly the same" doesn't mean they are.