When someone calls out and notices something randomly amazing. They usually say this at a time of disuse because it didn't make any sense.
When a person says something that was not meant to be said, but it was better off that way.
Steph: Omigod, Gary look at this text my bf sent me, it says "go fuck yourself in a hotel room with a bunch of niggers watching." Oop, wrong text!!
Gary: Ohhh, that is soooooooooooooooo retro.