Finland was invaded by the USSR multiple times and never got the eastern city of Vyborg (as well as a large chunk of national territory) back from Russia, even after the USSR collapsed.
That territory is the price for being in bed with the Germans -- it's like people conveniently seem to forget why it is so; my mother likes to talk about history when she has had too much wine, it's surprising there is anything left between Stalingrad and Berlin -- I still get mistaken for being Jewish which is ironic considering Jews didn't exist in the region I'm from after around 1944 - also about 25% to 30% of the civilian population. Given how much a pain in the ass the Winter War was (my grandfather volunteered for the Red Army in the 1930s) somebody likely decided it simply wasn't worth it at some point to have the Scandinavian countries be part of the USSR -- has it really worked out that bad in the end? Best of both worlds between capitalism/socialism and widely regarded as a region people want to live in.
