The system metaphor is a story that everyone--customers, programmers, and managers--can tell about how the system works.
Kent BeckHow good the design is doesn't matter near as much as whether the design is getting better or worse. If it is getting better, day by day, I can live with it forever. If it is getting worse, I will die.
Kent BeckThe business changes. The technology changes. The team changes. The team members change. The problem isn't change, per se, because change is going to happen; the problem, rather, is the inability to cope with change when it comes.
Kent BeckResponsible Development shares many practices with XP but the roots are different. Responsible Development's values are honesty, transparency, accountability and responsibility. These lead me to pairing, test-first, incremental design, continuous integration and so on because they support the values.
Kent Beck