I wasn't constantly naughty - and by constantly I mean every day. Why would anyone be naughty every day? What would be the point? I really don't understand why you don't think a good child would even exist.
Mistakes, yes, everyone makes mistakes. But deliberate naughtiness when you know you'll get slapped for the slightest thing! I wasn't stupid.
I agree that malice in under 12s is rare. :)
But I don't have kids, so I've not seen all this from an adult's point of view, just from that of a terrified child.