[herval]

I'm by no means a "purist" regarding any specific practice - I agree you don't HAVE TO test everything, write interfaces for everything and all in all write "awesome" code. BUT:

- how often do you interact with other programmers?

- how long is the usual life span of your code (in other words, what's the longest timespan you can expect to touch code you wrote in the past)?

- how big is the app/system you work on?

Imho, this approach ONLY works if the answers to above points are "never", "a few weeks max" and "very small"...

There's a time and place for every coding "style". Neither "TDD everytime" nor "cowboy style forever" are the definite answer.