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.
Another real acronym with a funny story (maybe only to old geeks like me) is STONITH.
Back when "high availability" meant two servers with shared storage and a "heartbeat" network connection, if one of the servers failed, the second one would notice there was no more heartbeat from the first and pick up the traffic so users would never know.
However, if the servers lost the network connection, there'd be no way to tell if the other server was still running and if both continued accessing the shared storage, they could corrupt the application data. So each server could take over if it noticed the other wasn't available by executing STONITH (Shoot The Other Node In The Head) basically sending a power down signal to the PDU, making sure the other node couldn't corrupt data.