It's what Hitler was saying he wanted, Lebensraum for a new German empire by conquering the "inferior" people of Eastern Europe. Western Europe probably didn't expect to be invaded, and who knows what kind of alternative history would have taken place if Britain and France hadn't got involved. Perhaps the Nazi's would never have been satisfied unless they were at war somewhere, or perhaps they would have had their hands full in the east. Nato countries today probably assume that Russia invading Ukraine isn't a prelude for Russia attacking Nato countries.