Economics
20% of Italy's population owned 80% of its land — the ratio kept showing up everywhere
In 1896, Vilfredo Pareto observed that roughly 80% of Italy's land was owned by about 20% of the population. Later analysts found the same rough 80/20 split recurring in business, where most sales come from a few customers, and software, where most bugs sit in a few modules. It's not a law of nature, but a strikingly common pattern of imbalance.