The "I voted" sticker plague is a terrible way for people to look at the nature of voting. This masturbatory self-congratulation demonstrates values that make us not vote as a nation. The idea that voting is some special event (not that it is not a privelege) instead of the common outcome/tool of democracy that it is creates a mindset where voting also is a burden instead of a privelege, where the person voting feels like what they are doing is a service to others that they should be lauded for enacting.
Additionally, anyone who brags verbally about whom they voted for is generally deluded about the process. Politics is not only a mess, but also such a corrupting agent that it is nearly impossible for any candidate to be a savior (see: Obama, who has disappointed us severely on human rights issues). In this lobbyist fueled system we live in, special interests are catered to rampantly, and most candidates cannot resist the allure whether consciously or subconsciously.