While I-Messages produce less defensiveness from children than You-Messages, it's obvious that nobody welcomes hearing that his behavior is causing someone else a problem, no matter how the message is phrased. Even the best constructed I-Message may cause your child to feel hurt, sorry, surprised, embarrassed, defensive, argumentative, or even tearful. After all, he has received a message loud and clear, that his behavior is unacceptable, troublesome or hurtful to you. Often, your child's first reaction will be one that lets you know that now he has a problem This is what we consider as high on the "emotional temperature" thermometer.
You will most always defeat your purpose if you continue to repeat your I-Message when your child reacts negatively to it. If you do, his emotional temperature will go even higher and he will resist you even more strongly.
To increase the chances that your child will hear your I-Message, you'll need to Active Listen and acknowledge his upset feelings. This shifting helps the child deal with his newly created problem and it also demonstrates the parent's understanding and acceptance of the child's reactions. It says: "I see that you're upset and I want to hear you." Listening gives the child a vent for his feelings, a chance to go deeper and if necessary an opportunity to do problem-solving. It lowers your child's emotional temperature.
So as soon as you become aware that your I-Message has caused a problem for your child, you'll want to shift gears from talking to listening. It's a temporary shift and doesn't mean that you are letting go of your needs, but it shows that you are interested in his needs and feelings as well. When your child feels heard accepted, the chances are much greater that he will be able to hear and accept your I-Message.*
*Excerpt from Dr. Thomas Gordon's P.E.T. Participant Workbook