I find these words of C.S. Lewis to be so true. When we are arrogant and consumed with superiority, we constantly have to look down on others - this is usually to make ourselves feel better than the "other." The trouble with pride, as Lewis points out, is that in the end, it stops us from looking up. I see this as a spiritual weakness - we fail to look up to God (not that God is only "UP" there in the heavens) and in so doing, prevent ourselves from receiving God's grace. God can't give grace to those of us who feel that we don't need it.
Romans 12:16 - Live in harmony with one another. Do not be proud, but be willing to associate with people of low position. Do not be conceited.
Living in Grace