Although he said it in a light-hearted way, and it presumably doesn't worry him as much as, say, world peace, or perhaps the failure of the Semantic Web to really kick off, one would hazard a guess that it does actually present a source of annoyance to the computer scientist, engineer and person of enormous (although possibly not enough) influence within the modern world.
At first glance this might seem to go beyond perfectionism, but just take a minute to imagine that something you did, that you weren't 100% happy with, was in your face over and over and over again every single day, and on top of that you had the knowledge that, during the years since you did it, millions upon millions of other people had also continually looked at it, typed it, written it down, printed it on t-shirts, said it on the television, on the radio, in films, to one another over the phone and in person, it would probably start to grate on you.
As it happens the issue doesn't really affect you too much now if you're not a programmer, since you no longer have to type the entire exact URL into your address bar when browsing the Web - the browser programs have become pretty good at helping us out by filling in the blanks. But it's reassuring to know that even insanely gifted people can suffer from the same levels of hyper-self-criticism as the rest of us - if anyone has good reason to be a little arrogant, surely someone whose invention literally affected vast swathes of humanity does. Yet he repeatedly seems to demonstrate a convincing self-effacing humility, which ironically makes me feel even more inadequate, but there you go.
I think we can probably forgive the double slash oversight. And let's face it, if the man wasn't so fastidious, he probably wouldn't have invented the Web and changed the world. If that's the level of regret that you have, you've probably done pretty well in life.
Written by Sue Smith