Hey Pandas, What's The Worst Mistake History Has Made?

I don't know if this exactly counts but basically during WW1 a British soldier spared a German soldier. That German soldier was Hitler. It sometimes makes me wonder how different the world would be if 1 solider had moved a finger an inch: No WWII, No holocaust, plus whatever advancements the descendants of the 50+ million people who died in those could have created.

This one always comes up and I still wonder if this didn't happen: Hitler was rejected twice by the Academy of Fine Arts Vienna , once in 1907 and again in 1908. What if he would have been accepted??

Crawling into land seems to have been a bad idea.

Creating humans. If I could go back in time and stop humans from ever existing, I would.