Some time ago, I picked up a “documentary graphic novel” about Korea and its people. It was praised by the Korea Times for its honesty, and painted views both laudatory and somewhat harsh and unflattering.
As part of its thesis, the book stated that geography and language are the most important factors shaping national character.
Geographically, the book contrasted island and peninsular nations with other ones. It said island nations like Japan and England are more isolated and harder to attack. This allowed more homogeneity, a culture of innovation and more development of traditions and character. Korea is a peninsula and the book stated peninsulas tend to have military value and that peninsular nations have often been invaded and so are more aggressive and insistent on local traditions - mentioning the Balkans as a comparison. It also contrasted these with mainland nations.
Though obviously too simple, the basic argument seemed to have some merit. I am not sure I had heard this argued before. Is it largely true? Are island nations very similar to other far flung island nations? Is there a peninsular people prototype, perhaps?