Higher prices
Russia (USSR) paid a higher price for Lenin and Stalin than all the wars it has fought, combined. (Some estimates of Stalin's excesses are upwards of 50 million.) Certainly his purges of the armed forces increased *their* casualties and civilian casualties manyfold.
I sympathise with the Russian people, but not with Russia. It sounds cruel, but they *deserved* Hitler's surprise attack and it was only luck (likely the Italian's incompetance at conquering Greece) that delayed the Germans long enough to keep the Germans out of Moscow. (You can guess this or that, but that's my opinion - the guns were heard in the playing hall of the USSR Chess Championship, still being held for morale reasons despite any danger.)
And I shudder at the results of THAT possibility. With Russia conquered, or at least crushed as a fighting power, the Germans could have poured lots of resources into France, Italy, North Africa, or anywhere else they wanted. D-Day certainly would not have occurred. The only real question is whether they would have been able to occupy England. Probably not, given England's command of the seas, but even *that* was close.
The most stupid thing the Germans ever did was declare war on the USA; if they hadn't done that, we'd have concentrated on Japan, Britain would have had less help.
Famous last RPG quotes: "I'll just shoot this fireball down the dungeon passageway..."