Clearly my favourite post is one where it spawned many comments, and in the comments I noted someone who could probably give a credible response to a question I had about a facet of fuel production that a real and clear answer had eluded me for some years. I was immensely pleased that I got way more that I asked for.
https://news.ycombinator.com/item?id=47969912 [How an oil refinery works]