> The Younger Dryas (c. 12,900 to 11,700 years BP[2]) was a return to glacial conditions which temporarily reversed the gradual climatic warming after the Last Glacial Maximum (LGM, c. 27,000 to 20,000 years BP). The Younger Dryas was the last stage of the Pleistocene epoch (c. 2,580,000 to 11,700 years BP) and it preceded the current, warmer Holocene epoch. The Younger Dryas was the most severe and long lasting of several interruptions to the warming of the Earth's climate...
> The Younger Dryas (c. 12,900 to 11,700 years BP[2]) was a return to glacial conditions which temporarily reversed the gradual climatic warming after the Last Glacial Maximum (LGM, c. 27,000 to 20,000 years BP). The Younger Dryas was the last stage of the Pleistocene epoch (c. 2,580,000 to 11,700 years BP) and it preceded the current, warmer Holocene epoch. The Younger Dryas was the most severe and long lasting of several interruptions to the warming of the Earth's climate...
https://en.wikipedia.org/wiki/Younger_Dryas
Everything was good for a couple of million years, and then everything got really really bad for over a thousand years.
What we think of as human history is the story of our recovery from the trauma of the YD?