There is something that I have had to get used to since getting here, sandwiches are everywhere. Back in the US buying a sandwich from a convenience store and you're taking your life in your hands on how old it is. Here every convenience store, off-license (liquor store), and grocery store have them, and frankly with the sandwich getting its namesake from here I'm not surprised.
With all the competition there is a lot of niche differentiation so I have been having fun trying a lot of different types of variations that I would never think of. It is really amusing to go into a seedy off-license and buy a gourmet sandwich with the lettuce still crisp because the are delivered three times a day.
With Sandwiches being the main thing being sold for quick food (The deli counters here are much smaller at the grocery stores that have them) I have not been able to figure out why I don't see more people eating while walking. It was a habit that I have picked up while in New York City. Everyone did it there. But here, I don't see anyone. The weird thing though is that no one looks at me strange when I do it here so it's not like there are any cultural rules against it.