“He that can compose himself is wiser than he that composes books.” – Benjamin Franklin
The trick is not to stifle yourself, but to express yourself in a constructive manner. Your points are secondary to your ability to communicate those points. Communication requires communion.
Also, if one is not willing to listen, why speak? Your best chance of having someone listen, is to cultivate the art of self-composure. By virtue of of your self-composure they will more likely be on the edge of their seat, ready to listen.
What the world needs is more self-composure. Then all else is possible. The highest form of composure comes from the very depth of your being.
Proper meditation is the gateway.