So the thing about history is that there's a tension between telling it how it really happened and the desire to "make it didn't happen." We all know about that last one. We do it every day when we edit our personal pasts to make us look --well, less dumb.
(Okay, I catch myself doing it all the time, but maybe you don't.)
Historians ought not fall into this trap, unless we are for some reason writing the history of me. Which you shouldn't do, I think. That is, you can, but you shouldn't pretend that it's history. Unless it's a memoir and
You know what, can't really defend that position, so never mind. The thing is, historians do sometimes write "make it didn't happen" history. Mainly they do it for political reasons. People get so het up over history. But military historians do it for another reason. They do it to make history cooler. Things that ought to have happened, didn't. Mongols didn't fight Roman legions. Iowa didn't face off against Yamato. Monty didn't punch Patton out and make him cry like a baby. We can't really make this stuff up. (Well, John Moser, Jacques Bacque and Victor David Hanson can. The rest of us, not so much.)
Or, we can. We can write "counterfactuals" or "alternate histories," where these cool things did happen. As a boy, I used to write or imagine counterfactual histories in which Britain and the Commonwealth did a great deal more of the dramatic heavy lifting during WWII. Don't ask why; I was a strange boy. Normal boys imagined alternate histories in which WWII went a great deal better for the Germans.
Now, I understand that, in some sense. The Germans were cool. Cool tanks, cool planes, cool uniforms. They make great enemies. It did always bother me, though. The Nazi state was arguably the worst thing that ever happened in the history of the world. (If you want to argue, you would probably point to Atlantic slavery, and the argument would be "which is worse, Nazis or slavery," and you'd be in pretty select territory of human evil.) My historical proxies were at least the good guys.
Except I was wrong. The only military counterfactual in which the horrors of Nazism did not take place is one in which the Nazis were defeated quickly and thoroughly. And only one nation, and one army, could do that. France.
I've never imagined, nor have I seen imagined, a counterfactual history in which France defeated the Germans in their "vabanque" attack of 10 May, 1940. And yet it could have happened. Many people blame the French for this defeat. And, indeed, mistakes were made. However, at least arguably, the key mistakes were made by my guys, my historical proxies.

Mistakes aside, the French did what the could. The British Commonwealth did not. It's a point I'm going to explore over several posts following, a few months too late to commemorate the fall of France.