The 50-50 Principle says that things that could go either way or most exciting looking forward, but are the least informative looking back.
Consider a huge example.
Can you remember back 12 years? For 35 days, the biggest news story in the history of the world was the tie vote in Florida. Indeed, in terms of frenzied interest it seemed like a much bigger story than the rather ho-hum election campaign that had preceded. Why? Because it was a tie, and thus, for 35 suspenseful days, could have gone either way. Bush could have won or Gore could have won.
On the other hand, even on a 2012 Election Day that might conceivably lead to something remotely similar, that whole five weeks seems intensely boring in retrospect. There were few large lessons to be learned, no vast new trends uncovered. There was just a tie.
And even in terms of what few large lessons there were from the recounts, the Accepted Narrative mostly managed to avoid learning them. The heart of the story is that more people tried to vote for Gore than Bush, but more Democrats, especially black Democrats in the slums, tend to be screw-ups, so they screwed-up filling in their ballots more. But, you won`t hear that, other than a comic reference to retired Jews of Palm Beach voting for Pat Buchanan.