Seoul and Beppu are different like night and day (go figure: one has 1 Starbucks, the other has coffee shops for probably every third adult of the 10.5 million inhabitants). In Seoul, I found many differences between Japan and Korea, but the countries do have some things in common as well.
Beautiful architecture and history
Small side streets with no names
Similar, delicious cuisine
Appreciation for high quality tea.
When it comes to tea, I definitely prefer the Korean one. The various possibilities: Schisandra, jujube, ginseng, and all the other other herbs: the variations and possibilities seemed to be endless! Japanese matcha and sencha are nothing compared to these various powerhouses. The bimbap, or Korean sushi, on the other hand was not that convincing. Usually the Korean sushi roll consists of spam/ham, surimi (fake crab) and mayo, which are not the ingredients I’d want to put on my roll. The nori is seasoned with some oil (grape, olive or other), and there is no soy sauce for dipping. The Korean soup is not as delicious as miso, but it comes for free with the divine kimchi and daikon, with refills! Point to Japan for this dish, point to Korea for the drinks!
Both of the countries also use a sign language I cannot understand. The difference is that in Japan I can at least read hiragana and katakana, whereas in Korea I had no clue what most of the signs or texts said. Luckily it is possible to manage without knowing Korean. For some reason, I automatically and accidentally spoke what little Japanese I can in the shops and restaurants. Maybe the numerous Japanese tourists had some to do with that, or then I am turning more Japanese than I thought I would.