When a person with a very strong personality tries to correct someone with a much softer and gentler personality, he can easily use an approach that would be appropriate for himself but not for the sensitive person he is talking to. People with strong personalities can handle, and frequently need, a forceful approach. Their feelings are not easily hurt. Approval does not motivate them as much as logic and an awareness of consequences. Disapproval does not frighten them, nor are they overly concerned with it. But people with sensitive personalities are strongly motivated by approval. Even a slight amount of disapproval is painful to them. If they are under a barrage of constant criticism, they lose their confidence, can beome depressed, and can even come down with serious illnesses. You have no need to use harsh approaches with such people. They appreciate kind words that they will repay the speaker of those words many times over. While it is wrong to manipulate others in ways that are not in their best interests, when you want to motivate them for positive reasons always use positive words.

From p. 207 The Power of Words R. Zelig Pliskin