The opposite of an opposite is a continuum. Non-duality does not preclude the existence of difference.
And the point I wanted to make here: all vices and virtues exist uniquely and in dynamic ways for all people. The way I express vanity may differ in small but significant ways from how you express vanity. The way I indulge anger may differ from how you do.
Practically, what this means is that it is easy to blind ourselves both to our virtues and our vices, because they do not exist in us precisely the way we seem them–or feel we see them–in others.
If I admire the courage, say, of Achilles, but do not express it in his way, does not mean I am not brave.
If I resent the egotism of another, that does not mean that it has not found a place in me, and nestled comfortably in some dark place in me I refuse to see.
I find the process of self discovery–which in many respects is also “other discovery”, because it facilitates deeper connection–endlessly fascinating. Some may see this as self absorption. Maybe they are right. I don’t know. Likely, the final answer is