Sorry, to ask such a basic question - but I don't get the point of Spaces. I mean, I've read what Apple says about it, but I just don't see the need in my workflow for Spaces. Am I missing out on some awesome functionality? Is there some secret trick to make Spaces super useful? I mean, I feel weird not using such a big feature of an OS. Help me out here... how do you use Spaces? Also, is there a big performance penalty for enabling this functionality (kinda like the way Dashboard sucks the RAM out of your system)?