How 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 system metaphor is a story that everyone--customers, programmers, and managers--can tell about how the system works.
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