expression
why in the world?; but why?; why did you?
Expresses surprise, disbelief, or exasperation at someone's action or situation. Often used as a rhetorical question or when seeking an explanation for something unexpected.
なんでまたそんなことをしたの？
Why in the world did you do that?
なんでまたここに来たんだ？
Why on earth did you come here?