Your Mind Is The Only Thing You Control Exclusively...

According to Napoleon Hill

You may spend your time and your energy -- both physical and mental -- in pursuits that yield the greatest return on your investment, or you may fritter it away on activities that will never bear fruit. Since your mind is entirely your own domain, you may choose to use it to constructive ends, or you can waste mind power and time on useless arguments that go nowhere.

There is a vast difference between a spirited intellectual debate and a petty argument. When you discuss concepts, your own knowledge is expanded through the interaction with another thinking person. When you allow yourself to be dragged into arguments about insignificant things, the result will be a dulling of both the mind and the spirit.