Re: to make things more (nu)clear
From the Russian PoV Russia is surrounded, In 1941 they had a modern military that was far bigger than Germany had and still came within a gnats breath of being beaten by superior tactics & experience.
Russia left Eastern Europe in the early nineties and have since watched all those countries joining both the EU & NATO. They now see a 400 million strong population block on their doorstep being led by two countries with form for heading East. (Ukraine would also be in NATO now if it wasn't for the near civil war with Russian backed separatists). To the South are all the volatile 'Stans and a vaguely friendly India sharing a distrust of China.
With their (blood soaked) history I don't see any reason for Russia to risk erring on the side of our 'obvious', after all the EU is trying to become a superstate and we're only ever one election away from picking another fan of Hugo Boss uniforms.