Although they're small, each of the three Benelux countries contains a diversity of culture, language, and tradition that defies easy definition.
Holland (the Netherlands) has its great divide, too, along the "three great rivers" -- the Maas, the Waal, and the Rhine. The northerners are straitlaced and Calvinist and (to hear the southerners say it) only know what to do with a glass of beer because they've been shown by the exuberant, Catholic southerners. Then there's the matter of nations within the nation. Friesland, Zeeland, and Limburg have their notions of separateness and their own languages to back them up.
Diversity is the greatest asset of the Benelux countries. The visitor from afar may be equally impressed by their shared characteristics, which include a determined grasp on the good life, than by the differences that separate them.