What am I?

While I'm a challenge for one and a rebuke between two, Yet I still have a direction for every number. What am I?

related riddles

You can hold me, fill me, but you can't pour me. I am needed to live but can be broken. What am I?

I lose my head in the morning and regain back it at night. What am I?

My rings are not worth much, but they do tell my age. What am I?