If we are to ever change our behavior we have to first allow for God to change our hearts.
There aren't many ways to get past our pasts but to totally have a change in our mindset. Though some believe that the emotions we feel are not in our control, the staunch reality is, everything that we do is controlled by the way we view and think of life.
Your heart is a muscle like any other, and it definitely needs the right nourishment, and exercise.
You have to train your heart, and train your mind to think positively, so that the things that come out of you will be positive.
If you choose to allow yourself to remain in a negative and depressing mind state, the things that will come from your mouth will be abundantly more negative than positive.
If you choose to train yourself to stay in a positive mind state chances are the things that flow out of your mouth from your heart will be positive as well.