There are the times when we really get into a state of prayer...and we don't ask, we don't plead, we don't try to reason with God - we may not even be consciously thanking Him - we just are. We sit. We kneel. We revel in His power and in His presence. And then something happens within our hearts and minds. Something that, having myself experienced far too infrequently (especially during exam time), begs me to ask this question of the Church and her historical heroes: why is it that the greatest saints have all thought of themselves to be the greatest sinners?
The saints are saints because they were constantly striving, during their lives on earth, to seek God. I think a major part of this authentic drive is humility.