Also used to express a pointless or chaotic situation such as an unorganized task where nobody knows what they should be doing.
Finally, it is used to describe a hopeless situation.
Fred: "Yeah- he's more 8 up than a soup sandwich".
example#2: Bob: "They want us to complete this assignment by next week, but no one knows who is supposed to be doing what"
Fred: "yeah, that's 8 up"
Example#3: Bob: "Dude, we are stuck in the middle of the desert, and I just ran out of water".
Fred: "yeah, this is 8 the fuck up"
PVT Snuffy- "Drill Seregent, I'm not 8 up, it's my rifle. It has been jamming and double feeding all day."
DS Slaughter- "You are still 8 up for failing to conduct proper maintenance of your weapon PVT! Your weapon will function properly of it is clean and lubricated!"