Save your time,
your energy.
Comparing yourself is a waste.
~
“How great a rest from labour he gains who does not look to what his neighbour says or does or thinks, but only to what he himself is doing, in order that exactly this may be just and holy,
or in accord with a good man's conduct. 'Do not look round at a black character,' but run toward the goal, balanced, not throwing your body about.”
~
Marcus Aurelius is not asking you to be indifferent to others, but advising you to avoid unnecessary comparisons and judgments that sow envy, resentment and distraction in you.
These " black character ", these behaviours or habits that can lead us astray, will drag you down if you are not careful. So you must " run toward the goal, balanced, not throwing your body about.", a metaphor for staying true to your principles and integrity without being led astray by outside influences.