Gemara:


Ein Ayah: Hashem’s leadership of the world brings every creation to the most lofty shleimut (completeness) that it can reach based on its level. However, regarding human beings, when a person makes choices about his personal affairs, he is able to have these matters bring him to a lofty shleimut. His shleimut is a function of the improvement of his actions to the fullest extent possible and especially in the area of following Hashem’s path. It is, therefore, imperative that he view Hashem’s ways in his heart and his mind as being the epitome of straightness and justice, so that he can straighten himself out and follow that path as well. If one views Hashem’s leadership as being one that does not care about iniquity and that someone can receive kindness and goodness in return for breaking laws, then the person’s moral framework will be ruined. This is because he will lose his path and distance himself from the source from which he could draw the flow of shleimut.
It is, therefore, worthwhile that one view himself as one who is deserving of Hashem’s mercy on him. Although he has done multiple sins, the pathway of repentance is rightfully open before him. In general, he should see Hashem’s willingness to open the doors for those who return as all based on straightness and great justice. In this manner, if the way of dealing with him is based on kindness, he will be able to contemplate and see the goodness of Hashem, and he will learn to go in the paths of justice.
In contrast, it is dangerous for one to entrench in himself the conviction that, according to the true rules of justice, he deserves a great punishment, yet he wants Hashem to, for whatever reason, treat him with great mercy, love, and compassion not according to the ways of justices. If he does so, then he is inculcating himself with the possibility, Heaven forbid, that because of love, the Divine ways of justice have been perverted. This can bring forth a poisonous idea in the area of his morality, which may influence him to not lead his own personal life along the ways of justice, and he may go from bad to worse.
Therefore, if one believes about himself that he should be in the worst situation, then Heaven forbid, he could actually cause himself to be in a bad situation, in order that he should learn from the way Hashem treats him about Hashem’s proper system of justice. This might awaken the attribute of justice in himself. This is why one should not open his mouth to the Satan but should consider in his mind and heart that Hashem’s treatment of him is a function of Hashem’s greatness, the lowliness of man, and the strength of his evil inclination. Doing so, he can conclude that even though the extent to which he left Hashem is objectively horrible, still His attribute of straightness and justice dictates that based on justice, Hashem should forgive and accept those who return from sin and recognize their iniquity. Then he can elevate himself in a path of justice and kindness and connect himself to Hashem and His goodness.