Answer:
You use it between your head and your toes, the more it works the thinner it grows.
The man who invented it doesn't want it. The man who bought it doesn't need it. The man who needs it doesn't know it. What is it?
I'm full of holes, yet I'm full of water.
If I have it, I don't share it. If I share it, I don't have it. What is it?
I am always in front of you, but you will never see me. What am I?
If lightning strikes an orchestra who is the one most likely to get hit?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?