A phrase that is used when something completely upsetting, shocking, and mind-numbing occurs that questions the meaning of your existence and the existence of everything else.
Can also be used when you are speechless and there are no words to describe your thoughts.
Friend 1: She applied to 18 schools and she didn't get into ANY. And she has a 95 average.
Short-hand for the word floccinaucinihilipilification, meaning the estimation of something as valueless (encountered mainly as an example of one of the longest words in the English language).