It is well for us that we are born babies in intellect. Could we understand half what mothers say and do to their infants, we should be filled with a conceit of our own importance, which would render us insupportable through life.
I don't have examples in my life of people who are all good or bad; I have deeply loved many people who are both, and I relate to those kinds of people on a far greater level.
Our duty is to be useful, not according to our desires but according to our powers.