Situation Normal All Fucked Up. Refers to a regular or normal activity or situation that, for a reason or another, turns awfully bad or doesn't go as planned. Was apparently used in the Vietnam war by soldiers when an unexpected event or attack took everyone off gard.
-So how was the party last night? Why do you have a black eye?
-It was cool at first, then a bunch of drunks came in and then it was complete SNAFU, bottle flew all over the place, and first thing I knew I got a blow in the face.