Something about TDD I never expected.

There is one thing I have always thought about programming, is that to do it, you need a couple of hours and to sit down and get in the zone. You really have to settle in and let it absorb you.

This is a bit of a problem when you have just an hour or less to spare because you know just as you actually get what the piece of code does, you need to give up and set off.

However, with test driven development, I can sit down, run bundle exec guard (A gem that runs all my specs for me when a file changes) and if I finished last while writing spec, I will put a spoof method like ENDED_HERE in the code, and it will flash up, or if tests fail, then I can jump straight to the piece of code that breaks.
I can sit down for just 10 mins at a time and make it pass a couple lines of spec and push up the code and go to work/lunch/friends/pub as needed.