8. Eat in the street / subway
Despite the fact that it may be convenient to walk while eating, in Japan, it could be seen as if you are taking food too casually and not paying the proper respect to the people who grew/made it. Broadly speaking, you are supposed to cherish your food. Even if you are just ordering from street vendors, you must eat it right there on the spot, or take it home. Under no circumstances should you walk away while eating it. For a Japanese vendor (except for ice cream and maybe some donuts shops), it’s very hard to understand that someone may want to enjoy a piece of cake right after purchasing it; a cake can only be eaten at home. Try telling them, “Don’t put it in a box, I’m eating it immediately,” and they’ll do the exact opposite.