Commentary on Meditations: B5:15

"these aren't the things you should focus on"

One should pay no attention to any of those things which do not belong to man's portion incumbent on him as a human being. They are not demanded of a man; man's nature does not proclaim them; they are not consummations of that nature. Therefore they do not constitute man's end either, nor yet any means to that end - that is, good. Further, if any of these things were incumbent on a man, then it would not have been incumbent on him to disdain or resist them; we would not commend the man who shows himself free from need of them; if these things were truly 'goods', a man who fails to press for his full share of any of them could not be a good man. But in fact the more a man deprives himself of these or suchlike, or tolerates others depriving him, the better a man he is.

What are these "things" that belong and don't belong "to man's portion"?  To answer that question, we should turn to Epictetus, who says at the very beginning of the Enchiridion:

Some things are up to us and some are not up to us. Our opinions are up to us, and our impulses, desires, aversions—in short, whatever is our own doing. Our bodies are not up to us, nor are our possessions, our reputations, or our public offices, or, that is, whatever is not our own doing. The things that are up to us are by nature free, unhindered, and unimpeded; the things that are not up to us are weak, enslaved, hindered, not our own. 

To rephrase Marcus, one should 'pay no attention' to our bodies, possessions, our reputations, our public offices and anything not of our own doing.  Man was not created for his body, possessions, reputation or for public office - these are not the end or purpose of man.  What we should focus on are things in our control - our impulses, desires, aversions and our opinions.

Lastly, let me comment on paying no attention to our bodies, possessions and reputations.  Some might ask in shock, "so I should not care about my body?!"  There is a nuance to understanding this.  Would you agree that you have little to no control over whether you get cancer or not?  You could live an entirely healthy, fit life and still have a stroke and die (like my son's soccer coach).  Indeed you can control how you eat and exercise and sleep, but ultimately you don't have full control over your body.  The same reasoning can be applied to possessions and reputations.