What chiefly enrages us against the man who injures or insults us, is the little account which he seems to make of us, the unreasonable preference which he gives to himself above us, and that absurd self-love, by which he seems to imagine, that other people may be sacrificed at any time, to his conveniency or his humour.
 Adam Smith, The Theory of Moral Sentiments (1759). copy citation

Context

“The object, on the contrary, which resentment is chiefly intent upon, is not so much to make our enemy feel pain in his turn, as to make him conscious that he feels it upon account of his past conduct, to make him repent of that conduct, and to make him sensible, that the person whom he injured did not deserve to be treated in that manner. What chiefly enrages us against the man who injures or insults us, is the little account which he seems to make of us, the unreasonable preference which he gives to himself above us, and that absurd self-love, by which he seems to imagine, that other people may be sacrificed at any time, to his conveniency or his humour. The glaring impropriety of this conduct, the gross insolence and injustice which it seems to involve in it, often shock and exasperate us more than all the mischief which we have suffered. To bring him back to a more just sense of what is due to other people, to make him sensible of what he owes us, and of the wrong that he has done to us, is frequently the principal end proposed in our revenge, which is always imperfect when it cannot accomplish this.” source