Answer:
What do you fill with empty hands?
All about, but cannot be seen, Can be captured, cannot be held, No throat, but can be heard.
Break it and it is better, immediately set and harder to break again.
A dagger thrust at my own heart, dictates the way I'm swayed. Left I stand, and right I yield, to the twisting of the blade.
Used on a diamond and left on a board. It's great for a gymnast his grip to restore. What is it?
Almost everyone needs it, asks for it, gives it. But almost nobody takes it.