I just got home from a "recount." Whenever the deciding number of votes between candidates on a ballot is less than a certain percentage, the affected candidates are allowed a recount if they so choose. In this case, the difference was 15 votes!
After we hand-recounted all the votes, which were originally counted by machine, we changed the count by one vote. The winner won by 14 votes instead of 15.
In this vein, think of the friends of either candidate. If only 15 for the winner stayed home, their candidate would not have won. The same rings true for the loser. If only 15 more people showed up at the polls, instead of staying home, that candidate would be the winner today.
You may look at this as just a local race in a small town, but multiply that by all the people who think their single vote won't count, especially in a presidential race. Of course the totals are much bigger, and the margins are much bigger, but add it all up, and all of your votes might make the difference. Presidential races are lost by thousands, but when there are thousands of people out there who think their vote won't count...think again!