I guess I'm still a relatively new Mac User, but I consider myself fairly technical and probably more savvy that your typical Mac user (though there are a lot of mac users who are far more savvy than I!)
Imagine my surprise when, while working tonight, I discovered that the Dock in Leopard is a Mirror! Yes, I'd noticed the reflection of the Icons, but tonight, I actually saw my cursor (in Terminal) moving as I typed... that caught my attention! At first I though, "well that's just amazing!" I had to wonder just how much work went into making that happen. Then, I discovered that some people don't like this!
Oh well. To each his own...