Sick of politics? Economist Gordon Tullock explains not only why it's permissible to stick your head in the sand, but it's in our best interest not to vote! This little PBS video is a great little primer on cost/benefit ratios, and the economics of deciding to do something or not - examples in the video include buying a pizza and voting in national elections.
Of course, Gordon makes two mistakes in his analysis. First, he assumes that there are strictly primary-selfish reasons for voting, and neglects the possibility that altruism plays a role. What leads me to suspect that altruism might is those little stickers, which people love wearing, saying they voted - humans who contemplate an altruistic act (e.g., donating blood) are more likely to do so if they're given an advertisement that they did it.
Secondly, even assuming his analysis is spot on, he's committing the naturalistic fallacy. The naturalistic fallacy is often thought of as the `is, ought` fallacy, because it often comes in the form of `X is natural behaviour, ergo, we ought to engage in X.` Behavioural research, especially human behavioural research, is often abused in this way. For example, research might show that murderers live longer, and are richer (I'm making this up, see), and that murder is an entirely natural part of human behaviour. However, just because it's natural doesn't mean we've demonstrated that it's morally good, or an action we should engage in. So, just because he's (possibly) accurately described human activities, doesn't mean that the description is the correct thing to do.
And now, an arbitrary picture of thistles and bugs: