Russia is a communist state, they controlled the USSR for a long time, telling the people what to do, making them comply with everything they wanted.I always feel a significant factor in this conflict is Putin not being able to allow a former Soviet state to slide further into the Western sphere and appear to be more successful and the social freedoms which come with it as it would cast questions domestically on the state of Russia.
Then the Berlin wall came down and everything changed.
The former USSR countries who lived under the whip now had freedom.
From nothing to all the benefits of the west, suddenly they could choose and who wouldn't want the shopping malls, the fancy cars, KFC, Mcdonalds etc it was a new era.
Putin wants they old ways back, he doesn't want the former countries out of his control any more.
If Ukrain was defeated then Moldova etc were next, he could very well have got his way.
All this "NATO on our borders" is just smoke and mirrors, he knows fine well that Nato would never start a war with Russia, there is no purpose for it.
All he has done is proved, Russia is a failed superpower and pushed Ukrain and all other countries further away.
Belarus will be next, Lukashenko will be ousted and Transnistria will be liberated.
Russia is in no position to help them any more. He cant support Syria or Libya now either so his influence is shrinking everywhere,
He has done a lot more damage to his country than just Ukrain.