When you communicate with others, be aware of your goals and keep your eyes on those goals. Most insults and derogatory comments are counterproductive and will not help you achieve your communication goals. If you find that you tend to insult a specific person, clarify to yourself exactly what your reasons for speaking to that person really are. Then ask yourself, "What is the best way for me to communicate if I want to reach my goals with this person? In what ways will I lose out by insulting him?"
Your goals might be that you want someone to do you a favor, to fulfill an obligation, to refrain from doing something that bothers you, for him to do something for his own benefit, etc. When the other person does not do what you want him to do after you have asked him a few times, it is easy to become frustrated and this frustration leads to insults. But this will just take you further away from your goals. Think for a minute and don't just react in anger. If one method does not work, ask yourself, "What other ways can I use that might motivate this person in the direction that I wish?"
Even if you might feel in a particular situation that insulting a person is what you feel like doing because you do want to cause him pain, ask yourself, "What are my life goals? What kind of person will I become if I insult him and what type of person will I become if I exercise enough self-discipline to refrain from insulting him?"
- From The Power of Words by Rabbi Zelig Pliskin