I can, however, only discuss Estonia, where I have been living for about three years now. My experience consists of two different countries within its borders. For the first two years I was living integrated in the Estonian part, and now I live in the Russian part.
Even though no Estonians like to talk about it, I see very clearly that some major problems exists, and this regardless of citizenship or color of passport. The Estonians use the term "ethnic Estonians," and these two major groups, the ethnic Estonians and those who have a mother tongue written in Cyrillic letters, quite simply hate each other. Not just dislike, but in most cases it is pure hatred.
There is a huge discrimination of anyone of Russian origin, who is not an ethnic Estonian. I, however, being a Westerner, and on top of that a Scandinavian, am quite accepted, but at present living together with Russians I feel utterly disgusted about the way I see Estonians behave.
Estonia is an ethnic volcano. Someday it may erupt. And admitting Estonia into NATO may very well move the time of the eruption much closer. The major argument Estonians give for joining NATO is to have a final and official stamp of approval for their treatment of the Russians.
As the common Estonian sees NATO as the number one adversary to Russia, they will undoubtedly use NATO membership as a slap in the face for non-ethnic Estonians: the nasty Russia is now far away and they will now have to adapt to whatever new rules.
This will in due time add more animosity between the two major groups of people in Estonia. Then we face a big problem within the borders of NATO that far surpasses the Greek and Turkish problem.
History has taught us that the use of force in changing and fitting people does not work in the long run. Estonia has tried it for 10 years with no success, and I think it is about time to involve other means without force. Only then can Estonia start to have a united people.