You already know how I feel about these things (here, here and here), but I found two fun articles on exactly the same subject.
First, there's an image on theoatmeal.com that describes why people pirate content. It's really long, so just watch on their site.
Second, Matt Gemmell takes a more serious approach, although the idea of what he's saying is basicly the same.
You should read the entire article. Here's a little preview:
But then you fuck us. First you fuck us with exorbitant pricing. Then you fuck us with inconvenience by not making your content universally available when we want it. Then you fuck us by treating every paying customer like a criminal.