“You can’t do it. You can’t add the feature. It’s too risky.
You’d have to change a core part of the program, and who knows what
kind of subtle bugs might creep in doing that? You got hold of the
source code and made sure that the license allows you to modify it,
but it’s too dangerous. Isn’t it?”
“Well, the proponents of Extreme Programming say not only that
you can, but that you should!”
“Extreme programmers aim for code that’s small, lean, mean,
and functional. To achieve the lean and mean, x-programmers always
do the simplest thing that could possibly work. They resist
the temptation to implement stuff that may be useful later, because
they assume they’re not going to need it. X-programmers are
fearless about modifying the code, so their software is always
functional. They will edit, refactor, or reimplement even large
sections when they need to add a new feature.”