Accidental anagram of 'Party Time' by an assembly worker at B&M when making bunting. Coined by 'Club Solo', a club-night founded during the famous Covid Lock-down.

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.