Mine is OOO for Out Of Office. I always misread it in my head like a ghost and it takes me a few seconds to process. It also doesn’t translate to speech—you have to say the whole thing.
Interested to see if others have similar acronyms they beef with.
FLOSS; only because I can only pronounce the second word as leeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeber.