Life is insecure. None of us are so powerful that that the game can't turn against us, and most of us could be traded like penny dotcom stocks if we didn't have a secure stake in something bigger than ourselves. We may not know what deals have been cut in secret, and we sure can't see the future. But we can know the law, and we can tot up the votes. That means we can keep our government answerable to us.
Nobody likes to lose an election.
You honestly think your candidate is the best for the job. You agree with the campaign speeches. You take time out on Election Day to go vote. It's a disappointment, no way around it. But the guy who's been elected is still your public official, answerable to you.