Question: I live with first ones ,they use me well! For the others I am hell! For the third ones I am useless,you can't touch me but you can see me! I am always there within you! Seek for me and and I'm right there! What am I?
Answer: Your Imagination
Question: My thickness is no more than a few centimeters, yet my depth can span to infinity. Although mundane, I intimidate most animals. When in my presence, you will inevitably follow me. What am I?
Answer: I'm a mirror.