Communion experience. Even if you have attained union with God, you still won't be content until you get to heaven and attain complete spiritual union with him. This is how God has made us. Attaining union with him on earth is just the first stage. Because God is so beautiful, you won't be satisfied until he is completely yours. In the same way, God loves us so much that he won't be satisfied until we are completely his. In heaven, both God and you will be completely happy together.