Yesterday we popped into Viet-Nam Bánh Mì So 1 (formerly known as Saigon), craving our usual cha fix, and though it was 7:30 p.m., a full half-hour before closing, we were greeted by words no one wants to hear — “no more sandwiches!” Then we noticed the little shop’s lights were off, to discourage more sandwich zombies from entering. Never before had we encountered such a thing — if anything, the shop has stayed open after closing to hook us up. Then we remembered a sign on the door a couple of days ago indicating that the place had run out of bread, and we put two and two together — the bánh mì boom is depriving loyalists of their comfort food! A call to the store’s owner confirmed it: We were told that this year there has been a “big difference” in volume. “Lately a lot of customers are different. At least 20 percent are different from the regulars — especially this week, so crazy.” On the one hand, we’re glad to see people getting in on the pork-roll action (after all, we’ve been pushing this sandwich for years), but on the other hand — if the new trend means earlier last calls, we are not happy.