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.
Might be unpopular, but as a non-English native I hate that Americans need to abbreviate everything into acronyms. POSTUS, SCOTUS, AWOL, ASAP. If it's not catchy as an abbreviation it needs a new name. I don't mind it so much in small settings, but when you read anything about America and all the comments are full of acronyms it's like a puzzle I never asked for.