I am sure this has been submitted before however, I think it is one of those talks that is worth watching once a year or so.
One of my all-time favorite talks, definitely worth revisiting.
This talk totally changed the way I look at programming. Highly recommended to anyone who hasn’t seen it.
He gave this talk twice. Once here at the infoq.com link, then again at Rails Conf 2012:
I like this Rails Conf version better because it’s a little more succinct, and, if you use Ruby, makes some better examples.