Don't waste your vote by not voting.
You've heard it from the demographically obsessed media, X group is more important than Y group because they actually get up and vote. Politicians target people who vote or they lose. It's as simple as that. Not voting sends a clear message to them, "I'm not worth your time".
This is a clear and obvious aspect of politics from the local to the national level, those who participate get things done.
Corporate America is exactly the same. People often talk about "voting" with their money, but this is usually in the context of choosing between a purchase and saving rather than picking between a number of purchasing options. Companies don't track failed sales, they track the people who buy their products. They don't give any heed to people who just save their money, looking instead at who is going to their competitors and why.
Keep this in mind if you're avoiding a purchase or spurning a choice between two political candidates you hate. If you want to send a message, staying home and keeping your vote to yourself only leaves the decisions up to someone else. Even if you throw it at Joe's Custom Built Rickety Fridges/Political Candidates your vote is better used than if it isn't used at all.