Joel's been posting stuff for years, and I'll sometimes just poke around his archives looking for some nuggets of IT wisdom. Joel is very good at laying out how not to do things, or why what seems to be the most intuitive approach to a problem is really the wrong way to go.
Today I came across this post from 2000 (which seems like ancient history, yet the article is refreshingly relevant). It's called The Process of Designing a Product, and what's so great about the post is ... well ... what it isn't. That is, it isn't a boring instruction manual. It isn't some stupid Wiki-How article that really conveys no actionable information. The article is, like, human. I mean, it's geeky, but it's written for geeks who don't realize that most people aren't geeky like them. And by most, I mean 99.9% of software users in the world.