Paradox of voting
The paradox of voting, also called Downs' paradox, is that for a rational, self-interested voter, the costs of voting will normally exceed the expected benefits. Because the chance of exercising the pivotal vote is minuscule compared to any realistic estimate of the private individual benefits of the different possible outcomes, the expected benefits of voting are less than the costs. Responses to the paradox have included the view that voters vote to express their preference for a candidate rather than affect the outcome of the election, that voters exercise some degree of altruism, or that the paradox ignores the collateral benefits associated with voting besides the resulting electoral outcome. (Wikipedia).
