It is said that our personality won't change easily.
No matter how wonderful school we go, or how a good teacher teaches, it is out of control to change our personality.
However, God can change our personality into good one when we hope and pray to be changed with heart, God gives us faith, renew our mind and thought and change our personality into good one.
God changes a hot-tempered person into calm-mannered one, a wild natured person into mild and gentle one, and even self-centered person into thoughtfully caring and loving one.
"With man this is impossible, but with God all things are possible." [Mathew 19:26]