Ok, my two best, out of a looong long line
First one happened when my first hubby and I appeared on the TV quiz show Gambit, many years ago. Before the recording they took us to the canteen for a meal, and I was chatting to one of the production people about my baby - Chris was a few months old at the time, and she said one of the other contestants was pregnant

So I wandered up to the lady with the tummy in a smock and congratulated her, expecting a lovely mummy chat about babies - and she looked at me blankly, then looked offended, and the awful truth dawned on me

Turned out it wasn't her, it was one of the other ladies
Second time was the recent debacle in Waterstones when my bag was setting off security alarms all over town, and I walked up to the assistant in there to explain, and it wasn't the assistant!
