I can't go near Subway... it has this distinctive smell that makes me want to hurl.
Now pastrami and swiss on rye with mustard -I don't call that simple. that's 4 strong flavors -too many to enjoy them properly. Brits would rarely mix meat and cheese in a sandwich -at least back when I lived there eons ago. Also, American "sandwiches" have far more calories and carbs that their smaller British cousins. If you ate them as often as Brits do, you'd soon be the size of a house.
btw you who come from a country when PB&J is a staple part of the diet are in no position to criticise Brits on their love of mixing things with mayo to put in a sandwich.....

And what is PB if not a "paste".....

:p