Self-esteem is the driving force behind our feelings. When we do an objectively evil act, our self-esteem (which is also objective) suffers. This is because our soul is clean and pure and angelic, and it is trapped in a non-place within the body.
The mind is the bridge between the soul and the body, and a section of the brain that deals with biological needs like food, sex, and sleep, is the primary organizer of impulses for health and survival. This portion of the brain is also connected to the mind, which is the software that manages conscious and unconscious processes.
The mind has, through the moral links to the soul, a sort of control over the biological-needs brain section, but at the same time, the balance can go against the brain due to environmental factors like watching a semi-clad girl, or becoming enticed (and greedy) by the glitz of the rich and powerful. These factors will cause the impulsive biological-needs section of the brain to run out of control of the mind, thus forcing the soul that is trapped in this body to be party to all sorts of evil deeds, such as promiscuity, bribery, gambling, drug addiction and so on.
As soon as this happens, the soul sends its dissatisfaction signals to the mind and the mind is made aware of a dissonance between the body an the soul. Since the soul wants one thing and under the control of the mind and the body is doing other things that are beyond control of the mind and fitting the biological needs, this conflict causes the mind to give up and the soul to become weak and unhappy, and a sense of disorder will ensue. In such a state, biological needs seem to assume more importance than they should, while the soul is unhappy and uneasy, and suffering.
The biological needs gone astray take their physical toll, while the mind receives protests from the soul which it translates into depression, guilt, shame, low self-esteem, and a vicious cycle of more of the same poison in order to feel even more pleasure that will provide an escape from the current pain. If left unchecked and untreated, this state of affairs will lead to mental instabilities and criminality, or both. And sooner or later depending on magnitudes and other variables.