What always frustrates me is that when people on here discuss deeply technical and/or meta-aspects of programming (e.g. type theory), it's taken at face value, but the same is not true of databases. They are generally treated as a dumb data store that you can throw anything into, and when someone explains why that's a bad idea, or why an academic concept like normal form is still applicable, it's met with criticism.

Even when it's purely performance-related, it usually gets a shrug, and "it's good enough." Cool, you're wrecking the B+tree, maybe don't do that. It's as if I said, "I'm using an array to store these millions of items that I later need to de-duplicate," and when someone suggests maybe using a set, I dismiss it.