I don't know why I get these ideas, but I'm not complaining
Plot bunny: Iceland goes fascist and evil. Why Iceland? Because, simply, no one would expect it. Like all the post-Viking nations, it's a socialist semi-utopia, with citizens that display a Tolkienesque obsession with genealogy, a GDP per capita at purchasing-power-parity that is sixth to none, and one of the largest geothermal heating systems the world over. Oh, and a lot of fish.
It works perfectly, now that I look again and put my thumb over "socialist": it's as homogeneous as water, with a population whose every member can point to the Norse scald or fair Irish lassie ancestor who brought the line there, and with 84% whom are members of the National Church of Iceland. There's also a company dedicated to using the Icelandic gene pool, which is, again, both homogeneous and well documented in terms of who is related to who, to better understand the human genome in general. This could be quite interesting. It's a shame I'll need to put it to rest, because it's got potential. But I'm writing something else right now, have three more things on back burners if that ever finishes, and what the fuck do I know about Iceland?
While I'm on the topic, some other countries that would make great, unlikly enemies: Switzerland, which is arguably the most paranoid nation on the planet: every citizen is in the military, even though it hasn't been in a war since a Catholic-Protestant civil war in 1847 which lasted less than a month and killed a hundred people at the most; South Korea, because they're the good guys, but if Korea is unified things could become very hectic given they'd be absorbing undocumented atomic weapons and cult-of-personality facism into a state which was ruled by it's own autocrat until 1987; and Singapore, not because it isn't already semi-fascist, but because I like the idea of a modern day city state and a bio-research Mecca holding the world hostage.
I also have one about a micronation started by a billionaire with a decommissioned aircraft carrier trying to become a microstate by bribing diplomatic recognition out of, say, East Timor. But I already have a plot outline to tack that onto.