For a long time they were the cheap but reliable type of disposable cup. Also very common, like qtips and Kleenex.
No idea if that is still the case, but they were common for a good reason.
The adherence to one type of cup is the weird thing. Most other places it seems there are many different types of cups, so there wouldn’t really be any trope about a particular cup.
snooggums@piefed.world 1 day ago
bluGill@fedia.io 1 day ago
Most people don't care about the color. For whatever reason the factory started making them in red so that is what people bought. Other colors exist if you look for them, but there is rarely reason to look. People just grab something cheap and move on without thinking. If the red was sold out they would grab the blue.