“[…] plans are useful, in the sense that they are proof that planning has taken place. The planning process forces people to think through the right issues. But as for the plans themselves, [they just don’t work in practice]” — from Made To Stick by Chip and Dan Heath
This provides a nice answer to the odd notion that being agile is an excuse to do away with all planning. It explains the intuition that planning itself is useful, even if plans aren’t.
I’ve only just started reading that book, but odds are good that there’s plenty more gems in it like this one. Thanks to Glen Lipka for the recommendation.
PS: I had to cripple the quote a bit, especially at the end, for it to make sense outside of the book’s context.