Where do you think people come up with their beliefs?

I think that people go through a hard time in life and they rather listen to other people then there self's. People shouldn't listen to what people got to say about them because then they start believing that their dumb, stupid, fat, or to skinny or just not good looking at all. I think that's where kid's start thinking that there not meant to be in this world and that's where kid's start going crazy not caring about what they do or what there parent's say to them at all. I think that if kids didn't listen to what other kids say about them kids wouldn't be going crazy or killing or stealing from stores.