In Havamal, which is the speech of "The High", i.e. the god Odin, there is a lot of wisdom of life in a society filled with animosity and danger. But even though the Vikings lived in a very different time than we do, there is a lot of good advice in Odin's speech. One piece of advice reads as follows, and I quote:
"Often words uttered to another
Have reaped an ill harvest:
Two beat one, the tongue is head's bane. Pockets of fur hide fists."
In short, it is said here that if you don't watch your mouth, you can get your head cut off! It can not be said any clearer than that. The Vikings knew that it was bad self-defense to go around provoking people.
The Vikings were tough and brave warriors. But they didn't take unnecessary risks. They were tactical. They swallowed their ego and pride to avoid unnecessary confrontations with an uncertain outcome.
This piece of advice is just as relevant today as it was over a thousand years ago. The chance of having your head cut off with a sword is, of course, much less today. But that is an insignificant detail. It's still good self-defense to watch your tongue.