good day vs what's new

good day

what's new

phrase
  • An informal greeting asking the other person what has recently happened in their life. A typical response might be "Not much; you?". The greeting is not always literal and may just be used to say hello. 

  • A rhetorical request for some real news, on hearing a report that was not news because it represents a continuing predictable and unsatisfactory situation. 

noun
  • The latest developments in a particular situation or a person's life. 

How often have the words good day and what's new occurred in a corpus of books? (source: Google Ngram Viewer )