Worry is a first-class ticket to the misery tree. It's like taking a lead-filled suitcase with you on a trip. It's of no value and a terrible burden to carry around.
In and of itself, worry is so powerful that it can keep you unconscious and miserable with minimal help from any of your other belief systems. If worry were money, we would all be billionaires, for it feeds on itself.
You can worry about anything, even about having little to worry about. You can worry for a solid year and still not change anything for the better. It is possible to worry endlessly, and no one can be secure enough never to worry. Worrying can be a way of knowing you exist. You worry and survive, so you form a belief system that says, "In order to survive, I must worry." Worry is a normal concern that is out of control.