Gamasutra interviews John Carmack, creator of Doom.

One of the humbling things that you find is that, no matter how good of a programmer you are, you write code, and you make stupid mistakes. And I am getting to be a huge proponent of really, really rigorous code analysis, because I have been going through pioneering these things, just squeegeeing through our code base, and every single programmer – from our best to our worst – they all make stupid mistakes, and they are unavoidable.