There are numerous causes of the demoniac mentality, but in this essay we shall broadly delve into only three: lust, anger, and greed. In the Bhagavad-gītā (16.21) Lord Kṛṣṇa describes these three characteristics as destroyers of the self-portals leading to hell.
The Supreme Personality of Godhead is the sole proprietor and enjoyer of everything. When the living entities forget this fact, they develop an intense desire to enjoy this phenomenal world. But they cannot be fully satisfied by such endeavors, and thus anger develops. Anger causes frustration, as in the story of the unsuccessful fox and the "sour grapes." The living entity is then forced to pretend to be a renouncer. But at the bottom of such renunciation burns the great flame of greed and the desire for enjoyment. This is only another stage of material desire. Therefore, unless one transcends this stage of acceptance and rejection of physical pleasures and becomes situated on the platform of the eternal self, one cannot understand the sublime message of the Lord. And without this understanding, one will continue to cultivate the demoniac mentality.
The only method by which one can elevate himself form the depths of demoniac depravity to the path of self-realization is to learn the injunctions of the scriptures and act accordingly. Chaotic and undisciplined activities contrary to scriptural instructions are actions performed out of lust. It is not possible to eradicate anger and greed through such acts of lust; nor is it possible to experience true happiness and divine elevation. Therefore if we wish to find the path to spiritual upliftment and eternal peace—the need for which is expressed in the lament "In the dispensation of providence, mankind cannot have any rest"—revealed scriptures are our only guide. Simply by executing the injunctions of the scriptures, we can become free from acts of lust and chaotic living.