R. Yochanan's opinion that one doesn't need to make a new bracha over food in a new locale. That is, no after-blessing nor prior to eating, even for the foods that do not need an after-blessing. But that's disputed, of course. And somewhat counter-intuitive, prioritizing the nature of the food or the meal over the logistics of location. Also, Birkat HaMazon over a cup of wine, and whether that can be combined over a cup that would have kiddush recited on it as well - which would be via a complicated scenario, wherein kiddush would take place after the meal...! Plus, why we don't bundle out mitzvot together. Except for when we do.