@Levanah Salt pepper and other spices used to be very expensive and therefore rare to find on mass in lower class food. On top of that many very vegetables we see for granted were only introduced later on by Columbus and others. I can't imagine Germany without potatoes. I think that food culture really developed only from the top (nobles -> rich -> etc) to bottom and mostly in the late middle ages. So the food wasn't really bad for high nobility (really sweet and sour with lots of spices) and become worse and more coarse the farther down the ladder you go. For example, a part of the flour from the mill would be sithed result in high class, middle class and coarse flour. Fish was rather widely consumed but meat really only in the upper classes. With all that said at least people back then didn't buy premade food and a stew you leave a long time virtually always becomes better. All in all the food in the middle ages wasn't really that good and really sweet but it laid the foundation for modern cuisine.
Regarding the Japanese arrogance you spoke about. Yeah, Japan while always really polite has always had a humongous problem with their feeling of superiority. This has led them into many troubles throughout history and Japan never really learned (Here in Germany the US and others made sure that Germany would learn about their wrongdoings. US reporters used to film in Auschwitz to show them but the Japanese emperor and his family never were brought to justice). While reading many novels it always surprised me how often the author would mention Japanese handicrafts and the superiority of Katana (which is actually pretty stupid as Japan smithing technology used to be multiple centuries behind Europes. They couldn't, for example, get their ovens as hot as Europeans nor could they control the heat to the same degree. In their defense, they didn't have a lot of iron so...). Authors would often introduce Japanese policies and never call it "our worlds" but "Japanese". That always used to strike me as odd. In their defense, Japan is really particular about their food and values it highly. Food takes a pretty big cut of their salary if I remember it rightly. However, many of their dishes are too sweet for my tastes. I feel like I'm the only one that feels oyakodon and tamagoyaki are usually way too sweet. There are a few good documentaries out there about the current rise of nationalism within Japan (Yeah that has never caused any disaster for Japan and certainly not two).