The small matter of cleaning one's shoes, for example, is not one of vanity alone, though of course it can be carried on to the point of vanity and even obsession and fetish. It is, rather, a discipline and a small sign that one is prepared to go to some trouble for the good opinion and satisfaction of others. It is a recognition that one lives in a social world. That is why total informality of dress is a sign of advancing egotism.
I wonder if the realization that one is a sinner is prophylactic against a preoccupation with self-esteem.