Advent is the time of waiting and of preparation.
Its purpose is to prepare us to recognise the God who comes to us in the midst of life. We need a season of Advent because God's ways are not ours and we can so easily miss his coming because God does not live up to our expectations. Our expectations are shaped by what we think we need to make us content. God's hope is for our transfiguration. He comes to gather us up into his work of saving love and saving justice.