Originating from the term oh my nan. "Are you my nan?" is a phrase that can be used instead of what are you doing? or what. Commonly used in South Australia and New South Wales.

Briefly, "the realization that each random passerby is living a life as vivid and complex as your own." Originally from the Dictionary of Obscure Sorrows, which has a lot more beautiful neologism definitions like this you might enjoy.