riddle - We all have it, but what is it?

We all have it.
At somewhere, Long and at somewhere, short.
On someone, thick and on someone, thin.
On somewhat, gold and on somewhat, black.
When someone doesn't have it, and we laugh.

What is it?

Answer

Hair

Although

Laughing at bald people isn't very nice :P

We all have it.

Everyone (or at least the vast majority) has hair somewhere

At somewhere, Long and at somewhere, short.

Some people have long hair, some have short. Also, head hair tends to be longer than, say, eyebrow hair

On someone, thick and on someone, thin.

Some people have thick hair, some have thin

On somewhat, gold and on somewhat, black.

Different people have different hair colours

When someone doesn't have it, and we laugh.

Again, laughing at bald people isn't nice. *finds bigger hat*