Migration, nutrition, political impacts
The invention of ice-making and ice-less air conditioning made the societal makeup of the United States vastly different. Suddenly the heavily populated North began to migrate south. In particular the elderly, whom are both more sensitive to the cold AND more likely to be conservative, began flocking to the south en masse. This effectively flip-flopped the North and South when it came to political leanings. The south used to be more liberal (somehow?!) Air conditioning had a lot to do with changing that. It did more than just make pleasant air, flash-freezing also made it possible to have vegetables, fruit, and meats frozen and re-thawed later without losing all their flavor. This was a benefit to the health of mankind, if it did (perhaps) doom the globe to global warming indirectly.