I think we have all heard the saying: "Garbage in garbage out".
This phrase may have a lot more to learn from than what you first think. A lot of people say this when people do something that others frown upon. Yet what can we learn?
What you consistently put into your mind is what you will consistently think about.
For instance, if you eat a lot of candy and sugary things then you will more than likely end up sick if you eat nothing else. Garbage in the mind, in the belly, puts out garbage of the mouth.