This sums up what I think of when think of Agile software development, "Agile is about creating better products, and making the process less painful along the way". I found it in the cooper.com article
The missing piece: How interaction design can add to Agile.
It reminds me of a conversation I had with another developer. We were talking about creating some kind of job tracking system so we can more accurately identify how much each widget costs. The conversation came down to, "Make it painless yet required". You don't want to tax the time of your producers, yet you want to more accurately capture costs per widget.
That is the idea of continuous integration. Whenever your code is committed, the unit tests on the build machine start running. They soon let you know if your changes broke any existing tests.
Some other quotes I like from the article:
"Agile helps people focus on the value the product delivers to real people"
"A focus on working code helps Agile projects stay honest."
"The Agile process does not provide tools to define key business or user experience objectives"