Good Riddles

Question: Walk on the living, they don't even mumble.
But walk on the dead, they mutter and grumble.

What are they?

Question: Having one, means having something to follow. Once you question it, it means having none. People seek it, but some do and some don't find it. What is it?

Question: I come in many different colors. I create boundaries to keep things concealed and safe. My best friend is a lock and I am also made of different materials as well. I love to travel: you can find me anywhere. What am I?

Question: How do you fix a broken pizza?

Question: Light hides me and darkness kills me.

What am I?