'Cause it's razor-sharp, you see. I'm a sucker for wordplay. I wish I could've used this one in an academic setting. One of the best puns I've ever had was junior or senior year of high school during those infernal CATS tests. We were taking the math portion of the test one day and the teacher gave us some blank paper to work out on problems with. Loudly, I said, "I guess you could call this 'CATS scratch paper!'"
Feel free to use that one, kids.