If testing costs more than not testing, then don't test.

Sometimes the problem has to mature before the solution can mature.

Learning research tells us that the time lag from experiment to feedback is critical.

Code wants to be simple... I had to give up the idea that I had the perfect vision of the system to which the system had to conform. Instead, I had to accept that I was only the vehicle for the system expressing its own desire for simplicity. My vision could shape initial direction, and my attention to the desires of the code could affect how quickly and how well the system found its desired shape, but the system is riding me much more than I am riding the system.

Responsible 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.

I don't like the feeling, but I've got to say that a little fear makes me a more focused, more responsible programmer.

I've known people who have not mastered their tools who are good programmers, but not a tool master who remained a mediocre programmer.