I'm not displeased by the election results last night. But.
Economists talk about "Market Failure" -- cases where markets will not lead to an efficient (Pareto Optimal) allocation of resources, because of: market power; externalities; asymmetric information; adverse selection; moral hazard; etc.
Good economists then go on to talk about "Government Failure". Just because the market isn't perfect doesn't necessarily mean the government will do better by intervening. Most of us don't understand government failure as well as we think we understand market failure, so we might not say as much about government failure. But at least we mention it.
The Efficient Market Hypothesis says that asset prices should reflect people's best estimate of the fundamental value of those assets based on available information. Changes in asset prices should reflect new information. When we see asset prices fluctuate over time without being able to explain those fluctuations in terms of the arrival of new information about fundamentals, we may begin to doubt the Efficient Market Hypothesis.
OK, so an election is not exactly the same as an asset market. But nevertheless: people are supposed to be voting for the MP or party they think is best, given their available information. So let's ask the same question: what new information arrived during the course of the election (or even since the last election) that could explain the opinion polls and the final results?
We could even make this personal. Did you change who you planned to vote for? If so, why?
(I didn't pay much attention to the election campaign. I figured it would take some big bit of information to get me to change my vote, and anything that big I would hear about anyway. And since it was so unlikely I would change my vote, I voted in advance, selling my option to change my vote in exchange for a shorter line-up.)