Why is that if you order food in, say, Starbucks, they put a napkin on the plate, under the food? It's not necessary - plates are perfectly functional inventions, aren't they? - and surely just a waste of a napkin? Would they not make massive savings if they stopped doing this? Is it some kind of branding thing?
Melted cheese on a plate: can be eaten. Melted cheese on a soggy napkin: not so much.
Why do they do it?!