Frank Sommers has written an interesting piece questioning whether Test-First Development is an Impediment to Creative Flow.
It is an interesting one, especially since I often find the opposite:
Test-First Development Allows Me To Flow
I often do my "play" in the tests. It is actually a nice warm, sunny place to jump around, experiment, and heavily refactor.
However, I am far from ridged on the 'test first' thing. I sometimes use it as a tool, and it often does depend on crazy things like: how I am feeling.
I certainly have no quarms making changes in my code that require a further refactoring back in the tests!