"I early learned that it is a hard matter to convert an individual by abusing him, and that this is more often accomplished by giving credit for all the praiseworthy actions performed than by calling attention alone to all the evil done."
~paragraph 9 of chapter 13: Two Thousand Miles for a Five-Minute Speech from Booker T. Washington's Up from Slavery: An Autobiography
No matter what the situation, who is addressed, and what the time period, this is something that never really seems to change. It makes sense that it would be this way. If all a speaker does is focus on all the negative things a group or person has done, that group or person will tend to get outraged and defensive; they will not be able to really listen to what the speaker has to say. If the speaker instead mentions the good the group or person has done, they would be more likely to listen; any criticism given in that situation--as long as it is given tactfully--would then be taken in stride; the group or person would be more likely to do something about it. In a situation such as the one Washington faced, this was a tactic he needed to use in order to make progress. It makes me wonder if he purposely chose to write this particular passage as a word of advise to others who try to make a difference.