Answer:
I never was but always will be. No one ever saw me but everyone knows I exist. I give people the motivation to better themselves every day. What am I?
You heart it speak, for it has a hard tongue. But it cannot breathe, for it has not a lung.
A house with two occupants, sometimes one, rarely three. Break the walls, eat the boarders, then throw away me.
I open wide and tight I shut, Sharp am I and paper-cut fingers too, so do take care, I'm good and bad, so best beware.
Face with a tree, skin like the sea. A great beast I am. Yet vermin frightens me.
You use it between your head and your toes, the more it works the thinner it grows.
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?