Many years ago, I recall reading in _Columbia History of the World_ that the ability to live in cities, that is civilization, began when people preserved their seed corn so that they could have multiple harvests during the growing seasons.

What I remember is that they summarize this as "Delayed gratification is the root of civilization."

And while this is pretty early in the history of the world book, I read no further because I doubted I would find anything more insightful in the subsequent hundreds of pages.

...

Years later I tried to find that quote and I could not. I still believe it is a valuable insight though even if I hallucinated it.