The old saying is that grace builds on nature. That teaching may explain something I have observed through life: the most sane among us are the ones who can be most convincingly Christian. What are the traits of the most sane?
1. No vanity-- their self-worth does not depend on possessions or ancestry or schools attended;
2. They do not seek power or control over others or to be the center of attention;
3. They have common sense;
4. They are indifferent to trivial matters such as the niceties of food or dress;
5. There are very few things they complain about or fuss over;
6. They have an instinctive sense of honor and shame--they have not forgotten how to blush;
7. They are naturally warm personalities;
8. They are eager to apologize for errors and to mitigate any harm that they have caused;
9. They do not have selective memories;
10. They are careful not to put others in dishonorable situations or to create situations of disrespect toward the dignity of another.
With that soil to work on, the Gospel produces great people. Without that soil, well, we are often left with pious neurotics that end up being "dis-angelists"--the dismal messengers who are the opposite of the good messengers or evangelists. Maybe, that is a reality the "new evangelization" should consider thoughtfully.
(Image below in public domain)