Yep, pretty much

こんにちは→Kon'nichi wa→Good day/Hello

Korean has more circular shapes, Japanese are more lines and Chinese reminds me of my English teatcher

*teacher

The Chinese says hello. (or the characters for you and good (ni hao) ).

I get their point, but to me they're just lines I can't understand ( I'm not racist, it's just that to anyone who doesn't understand that language, they're lines)

Korean says Anneyong Haseyo (I don't know the English spelling this was just a guess) but that is basically a formal way of saying welcome or hello