Riddle -Walk on the living, they don't even mumble. But walk on the dead, they mutter and grumble. What are they?

Question

Living I do not exist. Dead I am an inspiration. You always doubt me. But never reject me. I am what is given from old to young. Without me people would not learn mistakes. What am I?

Answer 1

There's more than one answer for this, but I think the most obviously might be leaves, which we all know make loud cracking noises when crushed underfoot.

My own feet is another. If I'm walking on my own feet while alive, people don't even mention it. But if was DEAD walking on my own DEAD feet, well that would arouse a ruckus.