The sniff test
Garbage most often wreaks of garbage. Poop smells like poop.
And disease smells of disease.
There are scents to the imbalance in the world and it's important that we recognize them.
It's wise to not kiss the guy with mono because you don't want to get sick yourself, right?
The same goes for your emotional and spiritual health. Envision there to be a huge bubble around you that extends 5 feet in every direction. That is your domain. What you allow in there can impact you the same way that a cold can affect your body.
Emotionally toxic folk.
Addicts to drugs, drama or lying.
Whatever or whoever it may be, inviting it into your world invites it to impact you, to morph you and to even lead you. And the longer it lives there the more normal it becomes. A smoker is indifferent to the smell of cigarettes because he is so used to it. But to the non-smoker, it smells like death. Thus he becomes immune to the sniff test that would tell him he's killing himself. He now has to look to other signs.
And many times, these folks would never pass the smell test. Culturally we don't place a lot of emphasis on this type of litmus test. We trust biology, cells and blood samples, but we don't trust our instincts that tell us so and so wreaks of instability and havoc.
We ignore the voice in our heads that tells us that this just doesn't make sense no matter how good it looks on paper.
The most basic truths to me tend to be the most powerful:
If it barks like a dog, it's probably a dog. And if it smells like the back end of a horse, then it probably isn't too far off from just that.