Imagine you were transported back in time to the early 1900s – say 1916 – in any large city in the United States: Boston, Philadelphia, Chicago, Minneapolis, San Francisco. Things would look different from today, but much would feel familiar. There would be automobiles with gasoline-powered engines, a telephone service, public transportation, clothing made of wool or cotton, electric lights, and appliances powered by electric motors. The Harvards, Princetons, Penns, and many other colleges would be there, though much smaller in terms of faculties and budgets than today, with much more emphasis on teaching rather than research. A government that sometimes succeeded but sometimes failed in delivering basic public services (trash pickup, police) would be a constant. Travel would be a great deal slower, but that would not matter to most people because they wouldn't be expected to journey as far, or get there as quickly, as people do today. Entertainment would tend to cost less and be performed live, although those new “moving picture palaces” would be opening up all the time. There would be more steam, more smoke, and more noise, but on the whole it would be a world you would recognize.
What would be truly different? One major difference is that since 1916, the US standard of living has gone up enormously. People at the lowest level of today's income distribution actually live better material lives than everyone but the wealthiest in 1916. A reason for this is that much of the population at that time worked on farms and earned notoriously low pay. And although those raising chickens and milking cows represented a much larger segment of the population than the urban workforce crowding the cities, the price of food was still very high relative to what people could afford.
Another major difference – and it is a huge one – is a change in what the average person was afraid of dying of. Today heart disease and cancer top the list of the USA's major causes of death. But in 1916 you would be most terrified by the thought of catching an infectious disease. (It was a fear validated by the influenza epidemic that would sweep the country three years later, killing an estimated 50 million people worldwide, more than the number who died in World War I.)