I'm not sure how to take 세상 좋아. It literally means 'Is the world good?'. If it doesn't fit in the context, there're two situations the phrase can be said in. When you could do something more easily than you expected, usually because of someone's help, you could say 세상 참 좋아.
In the other situation it could be sarcastic/a bit offensive like "내가 먼저 왔는데 너 먼저 해줬네. 세상 참 좋아. I came here first, but they did yours first, how nice the world is!(It's hardly fair!)"
병 itself means bottle or disease. Otherwise, it may come from 이뭐병(slang, very offensive), which is an acronym of '이건 뭐 병신도 아니고 (왜 저래? 희한하다, 어이없네 etc)'.
그치 comes from 그렇지. 그러치 ⇒ 글치 ⇒ 그치