A moral saint will have to be very, very nice. It is important that he not be offensive. The worry is that, as a result, he will have to be dull-witted or humorless or bland.
This worry is confirmed when we consider what sorts of characters, taken and refined both from life and from fiction, typically form our ideals. One would hope they would be figures who are morally good—and by this I mean more than just not morally bad—but one would hope, too, that they are not just morally good, but talented or accomplished or attractive in nonmoral ways as well. We may make ideals out of athletes, scholars, artists—more frivolously, out of cowboys, private eyes, and rock stars. We may strive for Katharine Hepburn's grace, Paul Newman's "cool"; we are attracted to the high-spirited passionate nature of Natasha Rostov; we admire the keen perceptiveness of Lambert Strether. Though there is certainly nothing immoral about the ideal characters or traits I have in mind, they cannot be superimposed upon the ideal of a moral saint. For although it is a part of many of these ideals that the characters set high, and not merely acceptable, moral standards for themselves, it is also essential to their power and attractiveness that the moral strengths go, so to speak, alongside of specific, independently admirable, nonmoral ground projects and dominant personal traits.
When one does finally turn one's eyes toward lives that are dominated by explicitly moral commitments, moreover, one finds oneself relieved at the discovery of idiosyncrasies or eccentricities not quite in line with the picture of moral perfection. One prefers the blunt, tactless, and opinionated Betsy Trotwood to the unfailingly kind and patient Agnes Copperfield; one prefers the mischievousness and the sense of irony in Chesterton's Father Brown to the innocence and undiscriminating love of St. Francis.
It seems that, as we look in our ideals for people who achieve nonmoral varieties of personal excellence in conjunction with or colored by some version of high moral tone, we look in our paragons of moral excellence for people whose moral achievements occur in conjunction with or colored by some interests or traits that have low moral tone. In other words, there seems to be a limit to how much morality we can stand.
(Susan Wolf, "Moral Saints," The Journal of Philosophy 79 [August 1982]: 419-39, at 422-3 [italics in original])
Keith Burgess-Jackson, J.D., Ph.D. 