In bowling you only use one to mark a spare. Four of them are used to form the letter W. So ask Sir Tim Berners-Lee, creator of the World Wide Web, what his biggest mistake was. A reporter did in a recent interview and his reply was that he is apologetic for forcing our hand, quite literally, to type the two slashes after the "http" in URLs. And he should be sorry!
The simple double-click-like action has caused an increase in carpel tunnel, a decrease in index finger fat percentage, unnecessarily excessive wasteful paper usage (you know, because we all write out URLs with a pen) and overall outcry by the Foundation for Under-used Characters, or F.U.C., for short.
Blast you, Sir Tim Berners-Lee, for your uniquely cool hyphenated last name and your unadulterated love for Michael J. Fox's attempts at a straight line!