What turned a once good child into a bad person?

When all they to do is make friends but people bully them instead. And when everyone around them makes fun of them and nobody wants to be around them, they snap and start making people be their friends. And then with bad influence they think that using force is the only way to get what they want. So they keep doing it.

Well if your asking why that happens I can help. I am not a parent but I do a babysitting job and read 5 books on parenting.

Let's say if the person has an absent father and a mother is left to take care. If the mother was nice and good she would handle it but would soon break the calm and cool with a child and have a nervous break down. The child will think he did it wrong and hate himself and become suicidal. But if she was to take the road of drugs she would make the child think he could do it too. Then the child will start selling drugs. Sooner or later the child will become sexual with the mother.

Those are some things a parent go do wrong to change a child. Trust me read a lot of books on these kinda things.

In essence, you're asking what motives habit, a psychological question. the answer is something from DNA or intelligence to the experiencing of nerve-racking activities. i trust there is something which will set off the "breaking undesirable" habit it would not in basic terms ensue. no matter if emotional damage or actual damage i imagine all undesirable habit should be traced to a previous journey.

Emotional and physical abuse turned me int to a total badass.

That ice cream you bought them a few years ago. It had bad people particles in it.

traumatic experience like watching mother die

crystal meth/drugs