>Could it be that TDD vs. tests-after-code is a highly personal thing? I personally find it easier to write good tests after I've coded something functional. Before hand, I know one or two fuzzy ideas of what I want to accomplish, but I can't list out the concrete, real-world test scenarios until after I've coded something, poked and prodded it, etc.

I generally find it better to engage in "top-down" development - specification->tests->high level code->low level code as it's cheaper to fix mistakes at higher levels first.

If I'm doing purely experimental code though - where I'm not sure of what I even want or what the output should be, tests are just a waste of time.

It also loses its effectiveness the more declarative the code is. If I'm essentially tweaking configuration or HTML there's no point.