I've always thought of voting as a way to express your own approval or disapproval of a node. Why rely on what others have thought of it when you judge it yourself?

A public service announcement from the public service announcement company

Kids, when you're spending those votes for the day, you may sometimes be tempted to "go with the crowd" for popularity's sake. I'm here to tell you that's a sucker's way to use this vital democratic tool. Although commiserating with your chums over node-voting habits may be a relaxing way to spend your workday, if that person is only willing to 'go with' you for the way you vote, then they're someone you don't want to spend your time with!

Seriously, the community's opinion of a node should not matter when you vote on it.
(yes, there's worst nodes and best nodes. But they exist as negative and positive reinforcement mechanisms, I think)