Gemara: Ulla expounded: That which it says, "Do not be evil very much …" (Kohelet 7:17), doesn’t that imply that it is only very much that one should not be evil, but he may be evil a little bit. Rather, [it is related to the idea] that one who ate garlic and his breath smells, should he once again eat garlic and have his breath smell [worse]?

Ein Ayah: The fact that evil exists at all is certainly part of the whole picture of the existence of the world. Just as there is nothing in the world which is not based on human choice that is only bad, so too even the evil that man chooses to do is not only bad. Rather, in the whole scheme of the world, there is a need for there to be people who chose to do bad things just as there is obviously a need for people who choose good things. This is the meaning behind Chazal’s statement: "Just as the praise of Hashem emanates from the righteous so does it emanate from the wicked" (Shemot Rabba 7:4).
The big difference between the place of the righteous and the wicked is in the people’s own place within existence. The one who does good is fortunate enough to be among those on a high level. He who chooses to do evil is among the despised, as the pasuk says: "Woe is the wicked man, for he will have retribution for his actions taken against him" (Yeshaya 3:11). There will be a clear correlation between the standing of his actions and the treatment he receives.
There is a net that is spread out before one who falls into evil behavior. His good side is disappointed that he is not counted among the good people because of the evil he has already perpetrated. Everyone has a desire in his soul to do great things, a trait that Hashem created so that people will provide ever more kindness in the world. One who sees that he is anyway not going to be great in a positive manner may feel the call to follow his evil inclination and be great in a negative manner. He might be attracted to being a major sinner, so that he can have great influence in some way.
This approach is a destructive fire that has consumed some people with great talents who fell into the trap of evil. First they started with small sins, after which they reasoned that they were so far from the community of the righteous, that they might as well increase the scope of their activity in the area in which they find themselves, which is evil. They deteriorated and caused deterioration in others until the point that they came to think that there is no difference for he who is not righteous between doing a little evil and doing a lot of it. He figured that once he is prominent in his wickedness, he will never embrace anything noble but will continue to increase in evil.
In truth, one should never say that his place is now set with the wicked. The deeper he falls into the mud of evil the longer it will take him to drag himself out and the more painful a cleansing he will need to purify himself. He should also realize that increasing evil will only make him dirtier and will not turn him into some "great villain." There is no such thing! Rather he is like one who ate garlic and continues to eat garlic, who will have the same smell, just that it will become more pronounced. As far as what has to happen in the world, fortunate people merit taking part in good things, and those who are not deserving become involved in that which is unfortunate in the world. The greater the filth the more unfortunate the person is.