Answer:
Used left or right, I get to travel over cobblestone or gravel. Used up, I vie for sweet success, used down, I cause men great duress.
I am always in front of you, but you will never see me. What am I?
A horrid monster hides from the day, with many legs and many eyes. With silver chains it catches prey. And eats it all before it dies. Yet in every cottage does it stay. And every castle beneath the sky.
You can only have it once you have given it.
My first is equality; my second is inferiority; my whole is superiority.
What has wheels and flies but is not an aircraft?