Answer:
I make everyone blind. You can't see me but I will always come back for you. What am I?
Never resting, never still. Moving silently from hill to hill. It does not walk, run or trot. All is cool where it is not. What is it?
I will disappear every time you say my name. What am I?
I run smoother than any rhyme, I love to fall but cannot climb. What am I?
I can be simple or I can be complex. I can be found in this riddle or in everyday life. I can be shapes or even colors.
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.