Extreme Programming Dangers

While doing some online research on development methodologies, I came across a useful analysis of how Extreme Programming (XP) can break down in real life, because each component methodology (lack of fixed design, pair programming, constant refactoring) is too dependent on the others for success. An example:

Constant refactoring (i.e. constant tweaking and improving of your code) creates an unnecessary overhead. Outside the XP world, occasional refactoring is welcome, as it is useful to check and improve ('de-fluff') your design; but constant refactoring makes no sense. In fact it only makes sense in the XP world, where the design is made up as you go along.