A Daily Practice in Stoicism Discourses 3.3 by Epictetus
"As soon as you leave the house at break of day, examine everyone whom you see, everyone whom you hear, and answer as if under questioning. What did you see? A handsome man or beautiful woman? Apply the rule. Does this lie within the sphere of choice, or outside it? Outside. Throw it away.  What did you see? Someone grieving over the death of his child? Apply the rule. Death is something that lies outside the sphere of choice. Away with it."
Goal of This Practice
Epictetus answers what the goal is in 3.5
"But if you can recognize in your own mind that you’re ridding yourself of some bad judgements, and taking on others in their place, and that you’ve transferred your centre of concern from things that lie outside the sphere of choice to those that lie within"
"Transfer judgments to things that lie within the sphere of choice, and I guarantee that you'll preserve your peace of mind, regardless of what your circumstances may be."