Do the people who love testing run JS or Python or something that compiles really quick? I've worked on some big projects and just to make a change, compile and run a unit test often takes 5-15 minutes. TDD works great if you have a trivial library in an interpreted language.
Understanding how to write tests in an economical fashion is a skill in itself. With care, you can write fast (and effective) tests in Haskell (and, I’m sure, every language ever).
