If a problem is fixable, if a situation is such that you can do something about it, then there is no need to worry. If it's not fixable, then there is no help in worrying. There is no benefit in worrying whatsoever.
On Destiny: "Our destiny exercises its influence over us even when, as yet, we have not learned its nature: it is our future that lays down the law of our today."
Human, All Too Human