Differentiation

"Care for nothing in yourself but what you feel exists nowhere else."

I've been pondering this part of my favorite phrase. Does it mean, if someone else can do something better than me, I stop? Does it mean, I stop when someone does things that I also do? What if they suck at what I do? What if they are better than me? At what point is the line drawn? Do I continue to do those things that others do, but care nothing about what I am doing?

These questions don't matter if this one is answered: Am I passionate about it?