Answer:
The man who made it didn't need it. The man who bought it didn't use it. The man who used it didn't want it.
No matter how little or how much you use me, you change me every month.
I am two-faced but bear only one. I have no legs but travel widely. Men spill much blood over me. Kings leave their imprint on me. I have greatest power when given away, yet lust for me keeps me locked away.
What is so fragile that saying its name breaks it?
What can you share and still have all for yourself?
What did the piece of wood say when he saw the screwdriver and screws approaching?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?