The Origin of the word "Worry"

Recently I have been putting an extra emphasis of focusing my thoughts on the future and the future I want to live into.

Part of that process has been for me to notice when I believe thoughts or entertain thoughts that aren't a part of my desired future.

For example, recently I decided to study the concept of worry (so that I could find antonyms of the word in which to redirect my thoughts). 

The word "worry" was in part developed from the concept of "to harass by rough or severe treatment (as of dogs or wolves attacking sheep)."

So, after understanding in more depth, I then went on to explore antonyms and I found this: calmness, certainty, cheer, comfort, confidence, happiness, joy, pleasure, sureness, trust, unconcern, advantage, contentment, peace, reassurance.

If we can choose to focus on either worry (wolves attacking sheep) or joy, which will we choose? 

If you could consistently shift your focus to joy, would you want to know?