Oh, I've done it this week.
There are two elderly ladies - sisters-in-law with the same surname - who both have connections in the parish, despite neither worshipping here in recent years. I got a phone call early Tuesday morning (like, I was still in my pyjamas and clearly hadn't had enough caffeine yet, early), from the daughter of one lady to tell me she'd died, and begin discussions of a funeral.
I don't know whether I misheard, or wasn't quite awake yet, or what quite happened in my brain, but I was firmly convinced, and yesterday in church I announced, that the wrong sister-in-law had died. Cue much confusion and consternation.
Now the lady who is alive, (but whose death I announced) is upset with me for upsetting all her friends and setting the gossip network on fire. The children of the lady who died are upset (very understandably) because their mother's death has turned into a circus of "Oh, isn't it a relief that [sister-in-law] isn't really dead!" rather than "Condolences on the loss of your mother." And my parishioners are, in their well-meaning attempts to make sure everyone is thoroughly informed about who is and isn't dead, only making things worse.
It's one of those days where I think, "If they were making a sitcom, they'd get a whole episode out of this."