Since moving to New York a few years back, I've been a bit confused about a couple very common, but manhatthanized, grocery items.
There are several, but the two that come to mind are milk and soda. Why do most soda cans in the City have the words "New York" printed near the rim? Is it a bottler thing, or is the product actually different? The other is milk. Why does most milk have a different expiration date in the city? It's usually about two days earlier? Is it all the difficulty in shipping in the city?