Curiosity did what?

Why is it that you can buy a cat all kinds of cat-toys that jingle, roll, and do other things to catch their attention, but they still prefer to play with things that aren't theirs? Why is the pencil, doll accessory, or USB plug (yes, we now have TWO useless cordless mice that don't have their plugs!) so-o-o-o much more enticing than the catnip-filled jingly ball?  It's a good thing she's so cute...