I'm not even asking if IABU, I know I'm not. I'm just posting this here for the enjoyment of the maximum number of MNers.
Today DD (aged 2 weeks) was wearing a very pretty sleepsuit in a cream sprigged print with tiny pink flowers on it. DM admired it. I said "yes, it is pretty, actually this print looks familiar to me, I'm sure I had a nightie in a print like this when I was little." DM agreed it did look familiar and this was entirely possible.
A couple of hours later, in the middle of a conversation about something else entirely, DM piped up "I remember where I've seen that print before now - (name of undertakers in home town) always had shrouds made of a fabric exactly like that."
When I had recovered sufficiently I replied "please feel free to keep information like that to yourself in future DM".