So, story time. For reference, I'm playing as the USA with historical focuses off. The war starts with, as usual, Danzig or War, but as soon as Poland capitulates Germany decides that the USSR looks mighty tasty and attacks. The western front is completely open, and a British naval invasion opens the gates for my fairly sizable army to go through. Germany eventually declares war on Belgium and the Netherlands as well, opening yet another front. The Anglo-American forces are starting to stall when my first armored divisions start rolling off the line, and with Patton at the lead we begin pushing into the heart of the Reich. They then call in Italy. Eventually Germany capitulates, and the combined Allies (which by this time are quite large) roll over Italy's comparatively puny armies. This whole time, Britain has been single-handedly maintaining air superiority and bombing the crap out of the Axis. Peace deal time, and the borders are restored to their previous states - only a little bordergore in the Czechoslovakia area.
Then the USSR bullies Poland into giving up its eastern territories.
I am having exactly none of that, so after a deal of buildup Operation Unthinkable kicks off in 1942, drawing in the Soviet Union, Republican Spain, Albania, Ethiopia, and Mongolia on Team Comintern and pretty much everyone else but the Asian countries on Team Allies. I'm rushing nuclear research so I can get the bomb ahead of schedule (mid-'44), but until that happens I'm just pushing the Russians back. They're actually fighting Japan at the same time, so it's a bit easier than it otherwise might be. Eventually, they capitulate when I nuke Stalingrad in '44. Peace conference, yadda yadda, and Japan takes a huge amount of territory out of the middle of Russia, leaving the newly-formed Russian Federation unfortunately split in half. This will not stand. Time for Operation Downfall!
This war actually draws in a shit ton of people, and spans from Bulgaria to the Home Islands. I get a little nuke happy, and by a little nuke happy I mean that I nuked Japan at least five times and several other countries at least twice. I even dropped two nukes on the same naval invasion just so it would be over faster. Japan capitulates, and eventually the last Japanese ally left standing is Revolutionary Iran. They go down, and it's finally time for the peace deal to end all peace deals. No more bordergore, a world free from fascism and communism...and the game crashes. I reload, only to find my "Puppet" CB against Japan is now invalid, and all I can to is change their government to a democracy. So I do, click "done" and hope for the best. And who do I find controlling the Home Islands (bar Tokyo)? Fucking Poland. Fucking Poland is now on the Japanese Home Islands. And it's a weird blue Poland too, because red-ish was taken by Commie!Poland when it broke away in a civil war. Which it then lost. Now I'm just pushing through to 1948 for the achievement. Pax Americana at last, and hey, no cold war! At the cost of millions of civilian lives, sure, but hey, that's the price of Freedom™.