Have you ever accidentally necroposted?

Yup, in my early days I was looking for an answer to something, did a search and an old thread came up, and I hadn't even considered looking at the date, I was just happy for an answer, and I was soon "reprimanded" over the fact I'd "necroposted", and I had no idea even what that meant.
The reprimander was pretty rude about it, and expected everyone to be as informed as he/she was.
There were a few choice words that went around my head as to how to respond, but I refrained from biting and let it go feeling just a bit attacked and injured.
Early learning days!