The Poles have no love for Russians, and who can blame them? Much is made of Hitler's invasion of Poland in 1939, not so much of the Russians invading Poland from the East as part of their Non-aggression pact with the Germans. Stalin's NKVD committed mass murder against The Poles in the Katyn Forest. Joe Stalin withheld Soviet forces from supporting Polish resistance forces battling the Germans in Warsaw in 1944, causing the Polish resistance to be crushed by German forces.
...and that's just the contemporary history of Russia's treachery against Poland.