Let's be clear, pride is different from healthy self-esteem. Pride is self-esteem propped up at the expense of others. It is the swelling of the heart filled with self-importance. Pride raises us up above others until we can look down on everyone. It is a spiritual cancer, eating up possibilities fro friendship and love and community.
Pride is a deadly sin.
Pride stands behind Hitler's war on the Jews, apartheid in South Africa, ethnic cleansing in Bosnia, and racism everywhere. In every case, pride causes people to believe that they are inherently superior to their brothers and sisters who were also created in the image of God. The Pharisee was so smug, so self-satisfied, that he needed, and he asked for, nothing from God. And nothing is what he received in Church that day. The terror, the deadly nature of sin, all sin, is that it always separates us from God.