Where does it start?
Children start off with an external locus of control—“he made me do it” “she hit me back first”! With appropriate nurture, boundaries and role modelling, children slowly begin to internalize their control, and own their actions and motivations.
Some children, sadly, don’t get the nurture and role modelling they need, get all kinds of shit dumped on them, and grow up without changing their locus of control. These become the adults who say dumb shit like “Look what you made me do” “I can’t get a promotion because everybody hates me” “I guess I’m just not lucky”.
God has something to say about this:
“When I was a child, I used to speak like a child, think like a child, reason like a child; when I became a man, I did away with childish things.” [http://biblehub.com/1_corinthians/13-11.htm]
Notice that it’s our thoughts that need to adjust, not just our actions. That’s why Jesus was such a hard-ass about purity when he said:
“You have heard that it was said, 'YOU SHALL NOT COMMIT ADULTERY'; but I say to you that everyone who looks at a woman with lust for her has already committed adultery with her in his heart.” [http://biblehub.com/matthew/5-28.htm]
In this day and age, therapy like cognitive behaviour, mindfulness, and emotional intelligence support that idea that we need to take control of our mind to take control of our actions and emotions. We can use the word sinful, or unhealthy, but ultimately, it’s making the change that should be the priority, not how the hell we label it.
C.S. Lewis noticed the necessity of cleaning up our thoughts; in The Great Divorce [http://www.amazon.com/The-Great-Divorce-C-Lewis/dp/0060652950], his angels minister to lost souls, not by threats, not by persuading them to behave better, but by challenging them to give up bullshit beliefs and perceptions.
An example is when one Ghost realizes his pet lizard (lust, go figure) is completely out of place in the culture of Heaven. His angel tells him he can stop the lizard, if the Ghost would only give him permission to kill it. The Ghost tries every other possibility—minimizing (“killing is too drastic”), procrastination (“some other day perhaps”), denial (“I’ll keep it in order now”), gaslighting (“why are you torturing me?”), distraction (“let me consult with a doctor”), false martyrdom (“I know it will kill me”), amongst other tactics. The lizard whispers more bullshit to the Ghost, until the Ghost realizes how worthless it is to hang onto these lies.
Once the angel kills the lizard, the Ghost turns into a strong man, and the lizard, a silvery white stallion. The book describes the new man (p.112):
“When he rose, I thought his face shone with tears, but it may have been only the liquid love and brightness (...) which flowed from him.”
This kind of transformation can only happen when we face ourselves honestly, take responsibility for ourselves, and tell our personal demons to shut the fuck up, get the hell out, and die.