Negative character traits come from discouragement. A person with faulty traits does not think of himself in elevated terms. He thinks he does not have the inner strength and potential to reach greatness. Only when a person recognizes that he has the potential to reach the most elevated levels will he strive for that!
-Sources: “Hoshlomas Hamidos,” p. 3; Rabbi Zelig Pliskin’s “Gateway to Happiness,” p.116