Web inventor: Sorry about the //
Tim Berners-Lee pretty much created the World Wide Web as we know it. And looking back, he says that while the "http" part of a URL makes sense, there's no particularly good reason for typing the double-slashes.
While Berners-Lee laments that many trees and work-hours could have been saved if he had left out the unnecessary // marks, I'm guessing that nobody was really all that hurt by their presence. But I guess it does show that in hindsight, pretty much anything could be done better.