Story Words: SONDER

n. the realization that each random passerby is living a life as vivid and complex as your own—populated with their own ambitions, friends, routines, worries and inherited craziness—an epic story that continues invisibly around you like an anthill sprawling deep underground, with elaborate passageways to thousands of other lives that you’ll never know existed, in which you might appear only once, as an extra sipping coffee in the background, as a blur of traffic passing on the highway, as a lighted window at dusk.

Poetic indeed...
Another meaning 

The realisation that every random person is living a life as vivid and complex as your own....

This word (or non-word) is a relatively new entrant into the world of words and has not been actually accepted by any Dictionary of repute...

It was used on a blog on Tumblr first and was created by "The Dictionary of Obscure Sorrows"

The origin is interesting and so is its meaning....

"As she sondered upon the moonlit walk, she pondered upon the pointlessness of life"

Here is a nice article on SONDER