The title of the article is Why Do Diners Across America All Use the Same Mugs? I instantly knew the answer- it's because they don't break. Well, they might if you threw them hard against a concrete wall, but in everyday use, they are super sturdy. I use one every day because it's tough, well-insulated, and most importantly, it fits in my car's cup holder, unlike all other coffee cups.
But the story is really about how this particular coffee cup came to be, and it's more interesting than just someone getting a good idea. Their first manufacturer was Victor Insulators of Victor, New York, who made porcelain insulators for high voltage electrical transmission. Their founder had developed a special method of producing porcelain that was dense enough to produce the high resistivity needed and withstand plenty of current. Victor Insulators did not set out to make coffee cups as a side gig, but they jumped at the opportunity when it was presented. Read the story of the common ceramic diner mug at Mental Floss.
(Image credit: Quercus acuta)