What do you think was Hitler's greatest Military Mistake?

@Allelse Yau. I think so as well. He could have focused on getting the UK.

I mean Blitzkrieging France, Poland, Austria and such is like running into your neighbours house with your buddies, cracking a few heads and taking over. While trying to Blitzkrieg Russia would be the equivalent of deciding to Run, on foot to the next town over, while trying to crack every head and take over everything in between, all the while trying to do it before a very large and very cold thunderstorm erupts.