Umm. The mahjong stuff might not be totally accurate since I've never played Riichi-Mahjong and it's been years since I've played mahjong in any capacity. Mahjong seems to be a game where almost every Chinese or Japanese person knows the rules, hands and scoring so when they play casually it's fun. It's only when you're playing as a pro or gambling in it where it gets a bit competitive and everyone's using meta-strategies to win.
The thick-pan base pizza is American and the thin crispy is Italian, haha. When I was a kid I remember the Pizza Hut near me was an actual restaurant with a red roof. It was buffet style and they had both thick and thin base pizzas. The trick was to eat only the thin-base ones so you could try all the different types of pizzas without getting full.
Kotatsu. Families spend entire days under it together in one room. I know that older wooden houses have little to no insulation and energy fees get really expensive if you turn the aircon on to heat your room so maybe this is a cheaper option? I've been reading that they tell you not to spend all day under it recently because it leads to DVT, bad sleep, blood pressure issues and it's easier to catch colds under it. Don't know how much of this is true.