They are my guiltiest pleasure. Almost.
Here's the thing. To me, listening to Slipknot is a lot like wanking. It satisfies a very basic need; but it's not as good as the real thing, and you wouldn't want any of your mates to catch you doing it. You'll feel good for a bit... and then just ashamed.
Subsequently, the phrase "listening to Slipknot" has a whole different meaning in my house.
Go on... have a quick listen...