- Don't get too fundamentalist about OO or functional programming. Each has its place.
- "Spend time hunting for an algebra" is somewhat obscure, but truly excellent advice, and I have spend a lot of my career doing exactly that. That has never been time wasted. This connects to a couple of other points. 1) Once you have an algebra, you have the basis of a good API for functional programming. (This point is not explicit in the list.) 2) The things manipulated by your algebra are also the basis of a good OO design.
- "Elegance is not a real metric." It is absolutely dangerous as a metric, because it is a subjective goal we all aim for, and can therefore be used to justify anything, no matter how dumb. That said, elegance is something to strive for in your day-to-day programming life. You know it when you see it in someone else's work, and you appreciate it. You see a small set of principles, implemented in one place, that can then combine in many ways to do many useful things. Hmm, sounds a lot like an algebra!