When you are either pissed off, hopeless, in trouble, or suffering, or maybe all at once. Literally means "why is thishappening?", but in a less nice way.
Guy1: homeless Guy2: takes the guy's stuff and hits him with a bat
Guy 1(crying and pissed): Oh fucking why?!
An exclaimation, generally used to describe either something surprising or something extremely cool, radical, awesome, or any other adjective from the Ninja Turtlevocabulary.