Bad as World War II and all its horrors were it could have been a lot worse if the Germans didn’t break the Molotov–Ribbentrop Pact.
The impact it would have had if Hitler and Stalin had remained “friends”would have been unfathomable. In all likelihood it might have saved a lot of Soviet and German lives but the outcome for the citizens of the other European nations would have probably been more devastating.
Japan probably would not have allied themselves with Germany and may not have attacked Pearl Harbor.
These of course are speculations stemming from a “what if ?” scenario, the fact is that Germany and the Soviet Union were allies at the start of the war. at a high cost for Poland.
Following are some impression on how that Soviet -German friendship looked like.
Soviet and German officials having a friendly conversation in the newly captured Polish city of Brest, September 1939.
German–Soviet military parade in Brest-Litovsk on September 22, 1939
Rolling Soviet tanks and German motorcyclists.
Common parade of Wehrmacht and Red Army in Brest at the end of the Invasion of Poland. At the center Major General Heinz Guderian and Brigadier Semyon Krivoshein
German and Soviet personnel amid parade display material.
Soviet and German soldiers in Lublin.
Polish hostages being blindfolded during preparations for their mass execution in Palmiry, 1940.
Ribbentrop taking leave of Molotov in Berlin, November 1940
Germany terminated the Molotov–Ribbentrop Pact at 03:15 on 22 June 1941 by launching a massive attack on the Soviet positions in eastern Poland which marked the beginning of the invasion of the Soviet Union known as Operation Barbarossa.