First, market research must be taken with a grain of salt. (Polls leading up to the election showed Barak Obama jumping to a 12 point lead.)
Second, never underestimate the power of emotion and empathy. (Hilary Clinton's much publicized show of vulnerability and emotion momentarily humanized her in a way that connected with voters, particularly women.)
And lastly, leaders must never lose their sense of humility. Americans love underdogs. (Barak Obama, fresh off his victory in Iowa, began acting like the front runner the media had suddenly hailed him to be. Referring to Clinton as "likable enough" was a rare show of hubris.)
We see these same mistakes committed every day in the world of marketing. Focus groups taken as gospel truth. Rational appeals from marketers desperate to argue customers into buying their products. And the overconfidence that one-time underdogs adopt when they suddenly get hot (Apple? Facebook?), forgetting that it was their challenger status that made them attractive to us in the first place.