So this has just happened: I stumbled upon a #StackOverflow question that looks relevant to my interests.

I read the answers and saw one that is long and quite good. I wondered if it mentions some important exceptions... and it did. "What a great answer... I know all of this, but it's good to see it written".

I tried voting for it, and saw an error message: "You can't vote for your own post".

I indeed wrote it myself, twelve years ago.