I have often been amazed at how many people who are not saved are less peevish than those who are saved, who go to church, who strive to love and obey God.
Most "non-Christians" are not under law, and therefore they are not striving to be obedient.
For that reason, they have more grace flowing in their lives.
As soon as most people get saved, however, they are levelled with all of these deamnds from their pastor, their church family, or their own flesh-and-blood family.
The law brings out sin, brings out flesh, and causes us to be wrathful, peevish, short, difficult with others.
Check out the works of the flesh:
(Galatians 5:19-21)
Check out the fruit of the Spirit
notice that it has nothing to do with us. It is not "fruit of the believer", but the Spirit of God, who works within us, and flows outside of us.