The best human trait? Scripture says:
Total Depravity
Because of the fall, man is unable of himself to savingly believe the gospel. The sinner is dead, blind, and deaf to the things of God; his heart is deceitful and desperately corrupt. His will is not free, it is in bondage to his evil nature; therefore, he will not--indeed he cannot--choose good over evil in the spiritual realm. Consequently, it takes much more than the Spirit's assistance to bring a sinner to Christ--it takes regeneration by which the Spirit makes the sinner alive and gives him a new nature. Faith is not something man contributes to salvation but is itself a part of God's gift of salvation--it is God's gift to the sinner, not the sinner’s gift to God.
(Genesis 2:15-17, Romans 5:12, Psalm 51:5, 1 Corinthians 2:14, Romans 3:10-18, Jeremiah 17:9, John 6:44, Ephesians 2:1-10)
David N. Steele & Curtis C. Thomas The Five Points of Calvinism