As far as massachusetts is concerned, I disagree. I was born and raised here. I know "Fluffernutter" is a rather famous product, but no one around here really eats them with any sort of frequency. You can't go to a sandwich shop and order one; there aren't storefronts dedicated to making one.

What we do, is the roast beef sandwich. Thin shaved roast beef, cheese, mayo, barbecue sauce is the classic combo. There are many many stores that sell this, and only this.

The other odd one is New York. Although lox and cream cheese is my favorite thing in the world, how did they not choose the hot dog? It's as much a sandwich as a lobster roll is.