Epictetus begins the Enchiridion with the single most important sentence in practical philosophy: Some things are in our control and others not.
In our control: our judgments, our impulses, our desires, our aversions. Not in our control: body, reputation, property, position, other people's opinions, market conditions, the fact of ageing, the fact of death.
The Stoic observation: virtually all human suffering is produced by applying effort and emotional investment to the second category while neglecting the first. The person anxious about their reputation is trying to control something not up to them. The person attached to a particular outcome is trying to control something only partially up to them.
The Bhagavad Gita arrives at the same distinction from a different direction. Karmanye vadhikaraste ma phaleshu kadachana — you have the right to action, not to its fruits. This is not fatalism. It is the most precise description of where agency actually lives — in the quality of the action, not in what the world does with the action. The confusion of the two categories is not a strategic error. It is a philosophical one. And philosophical errors require philosophical remedies.
The diagnostic: notice where your anxiety lives. What specifically are you trying to make happen that depends substantially on factors you cannot determine? Every unit of attention directed there is a unit not directed toward what you can actually influence.
The energy that was going toward the uncontrollable becomes available for the controllable. The result is not resignation. It is focused action that the anxiety-driven attempt to control everything actually prevents.