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.
I learned about a11y like a year ago, and thought it was 1337 speak for ally until I looked it up, and only then (like 20 years after first seeing it) did I realize what i18n meant.