This afternoon, I had a problem. Django is a popular tool for building websites, and the Django administration tool is designed to show individual tables from a database and lists of their contents. I had a fairly complicated problem whereby a related, generic table was supposed to have-- but may not have had-- data associated with items in my target list. This relationship is tenuous, meaning the database doesn't understand it natively; there has to be some external process that manufactures the relationship with every request for data. Django does this fairly nicely with a plug-in, but the plug-in doesn't always play nice with the administration tool.
I spent about two hours puzzling it out until I finally found the answer on Stackoverflow. When I found it, I facepalmed.
I had written that answer. In fact, not only had I written that answer, but at the time I had written it, barely 14 months ago, I was considered one of the world's leading authorities on doing weird things with the Django administrator.
I've forgotten more about Django than most Django heads have ever learned. Unfortunately, "forgotten" seems to be the operative word today.