Tearing someone else down does not build you up. It merely shreds any sense of decency you thought you had. Those who indulge in such things stake their claim to the bottom of the barrel.
If a person disagrees with you, it does not make them the enemy. They have a different perspective, and you might be able to learn from it. At least you can see where they have been led astray.
Do not be quick to think you are right. People tend to extol their useless opinions. Be the first to question your beliefs, and you will be better prepared to defend them.
What most people think is usually wrong. Crowds have a tendency to muddle everything. Too many voices, and nothing can be heard.
Sometimes it is best to just stop talking. Silence is golden, especially when there is nothing nice to say. Listening is preferable to yelling any day.
A discussion becomes an argument when the topic gives way to the contending egos. If this continues, serious harm could be done. Better to let it go, before you speak the words you will regret.