Arbitrariness of the sign
There is something oddly hilarious about looking over these linguistic coincidences, like learning that there's a language where "beter" means "worse" or "bhlak" means "white". Maybe it's a kind of nervous laughter in the face of the unfathomable prospect that "they are merely conventional signs!".
By the way, arigato/obrigado has turned out to be another of these coincidences, despite the real influence of Portuguese on Japanese.
