I was wondering how Kant, or even Mill might respond to the issue that when doing the righteous thing, say standing up for yourself against a bully, or somebody who wants to impede on your rights, you cause said person discomfort.
The only purpose for which power can be rightfully exercised over any member of a civilized community, against his will, is to prevent harm to others. His own good, either physical or moral, is not sufficient warrant.
As for Mill the above passage seems to preclude standing up for what is right if it causes harm.