“There is an universal tendency among mankind to conceive all beings like themselves, and to transfer to every object those qualities with which they are familiarly acquainted, and of which they are intimately conscious.” (David Hume, "Of Miracles and the origin of religion.")

“the boundaries of what is possible in moral matters are less narrow than we think. It is our weaknesses, our vices and our prejudices that shrink them. Base souls do not believe in great men; vile slave smile with an air of mockery at the word liberty.” (Rousseau, Social Contract, 195)

I've become more and more convinced that the traits we have--our weaknesses, predilections, fears, and hopes--, we attribute to others. If we are unmerciful, we expect others to be unmerciful; if we are suspicious, we assume that others are too. It thus comes as a surprise to us when people do kind or generous things that we don't expect them to do, because maybe we would not have thought to do it ourselves. I like this quote by Rousseau for expressing how this human trait limits us. 'base souls do not believe in great men;' we have a hard time getting above our natures. At the same time, the power of example is inestimable. I guess the moral then is to be unassuming.