Why Mom Did What She Did

I have always poked my potatoes with a fork before baking them. I
stab them good and hard at least twice on each side. Mom always
stabbed her potatoes. . . Well a few days ago I was in a big hurry
and thought "why did Mom stab the potatoes anyway? Surely they will
bake up fine without being stabbed." Why? If you don't you risk an
EXPLOSION!