Trying to round up the usual suspects

By that, of course, I mean the countries in Europe that have not yet visited Eff You. I have large holes in my Africa and Asia collections, and a few holes in my South America collection -- and I don't even want to talk about Pacific island nations -- but I have a dirty half-dozen that have been recalcitrant about visiting Eff You: Monaco, San Marino, Lichtenstein, Vatican City, Montenegro and Kosovo. The first four are among the six European microstates -- Andorra and Malta have already come by -- while the last two are Balkan countries. All six have steadfastly refused to visit Eff You, and I want to know why. Come on, people, represent!