In most coffee shops these days, you'll find that the small, medium, and large coffee cups all use the same size lid now, whereas even five years ago they used to have different size lids for the different cups. That small change in the geometry of the cups means that somebody can save a little time in setting up the coffee shop, preparing the cups, getting your coffee, and getting out. Millions of little discoveries like that, combined with some very big discoveries, like the electric motor and antibiotics, have made the quality of life for people today dramatically higher than it was 100 years ago.

Paul Romer [3]