How are the Nordic countries and Balkan countries similar?

They're not. However a situation between these two areas is similar. Most people tend to consider the Nordic countries all similar. i.e. Swedes are like Norwegians etc Whereas people who are from this region have very distinct and separate identities. There are the three countries considered Scandinavia. Sweden, Norway and Denmark that are separate from the rest of the Nordic countries. There are jokes about these three that illustrate some of the differences that they find within themselvs. From Images of the neighbour: Reciprocal national stereotypes in Scandinavia by Thomas Hylland Erikson 1997 The Swede is always depicted as a rich and arrogant child of the Enlightenment, the Dane as a slightly decadent hedonist, and the Norwegian as an uneducated, often stupid country bumpkin. A Swede, a Dane and a Norwegian are shipwrecked on the proverbial desert island. A genie appears out of thin air, informing them that they can each have a wish granted. The Swede immediately says, "I want to go home to my large and comfortable bungalow with the Volvo, video and slick IKEA furniture." So he vanishes. The Dane then says, "I want to go back to my cozy little flat in Copenhagen, to sit in my soft sofa, feet on the table, next to my sexy girlfriend and with a sixpack of lagers." Off he flies. The Norwegian, after giving the problem a bit of thought, then tells the genie, "Cor, I suddenly feel so terribly lonely here, so I guess I wish for my two friends to come back." But even here people petition whether Finland and Iceland should not be included into Scandinavia. And it is similar with the Balkan countries. They are clumped together and considered one is just like the other. However, there are strong and adamant divisions within the the people who inhabit this areas. The countries of the former SFR Yugoslavia all have very strong identities and very separatist feelings about their neighbors. Croatia vs. Serbia Serbia vs. Montenegro Macedonia vs. Northern Greece Macedonia vs. Bulgaria Albania vs. Macedonia Albania vs. Serbia Kosovo vs. Serbia Kosovo still is not recognized by Serbia as a separate nation. The last entire decade of the 20th century the Former SFR Yugoslavian countries were spent in wars for independence, border and cultural disputes. So a similarity between Nordic and Balkan countries is that from outsiders each region and its countries seem very similar if not practically the same, whereas from inside the region these countries find themselves different from their neighbors and have very strong independent identities.