Sledgehammer to crack a walnut
You should see the walnuts from my neighbours' tree. I picked some "fallers" up a few years back, eagerly anticipating lovely sweet, soft nuts just like the ones we used to get from "Auntie Pam"'s tree when I was a kid and nothing like the bitter, dry things you get in the supermarket. I had to use a bench vice to crack them. The bloody nuts were the size of peas; the rest was solid shell. Just for laughs I put one under the wheel of my car and drove over it - it survived intact.
Biting the hand that feeds IT
