Germany started the war. The Soviet Union was forced into it much later by Germany declaring war on them.
> Poland lost 20% of population in WWII
No country lost more people in WWII than the Soviet Union, as I'm sure you're aware. Your feelings of huge loss are shared by the Russians.
> You may also notice that Poland and Ukraine are on perfectly friendly terms with Germany.
It's just because Germany left Polan much longer than the Soviet Union did. With time, you'll also "forgive" the Soviet Union, their crimes pale in comparison with the Germans.
> It's really hundreds of years of Russia trying to subjugate us.
Poland has been occupied by many other countries[1]. It was Prussia and the Autro-Hungray Empires that occupied it for the longest, not Russia... that's how European politics always played out, a big struggle for smaller states living between the bigger ones... why single out Russia? Probably only because it was the latest invader and memroy from previous occupations is fading.
Do you really believe being hostile to Russia will somehow be benefitial to Poland in the longer term?... if history is anything to go by, you should watch both West and East of your border while trying to stay "friendly", or at least neutral, in relations with both.