Answer:
I only exist when you are here. Where you never were I can never be.
Though not a plant I have leaves. though not a beast I have spine. Though many wouldn't need me I am more valuable than wine.
I am made of wood but can't be sawed? What am I?
Tool of thief, toy of queen. Always used to be unseen. Sign of joy, sign of sorrow. Giving all likeness borrowed.
Digital white-out.
Which popular cheese is made backwards?