[Jormundir]

The rule would be better if it was:

Realize the effect you have on the people around you. If you're are negative, you will make the people around you feel negatively, if you are positive, you will make them positive.

It's more powerful than advice telling you to cut people out of your lives. You will have a better effect on the world.

To me, blaming the people around you for your own negative feelings is part of the 'blame others for your own problems' negative cycle of excuses. Make the people around you positive by being positive, by being a good friend: listening, inspiring, generally caring.