why study theology?

I'm taking in J. I. Packer's Knowing God (again), this time in audiobook. It's such an excellent work, and truly a Christian classic! 

In the first chapter he answers the question, "who needs theology?" The question is posed by someone who finds the study of theology unnecessary, impractical, and boring. Maybe it was of interest in past days, but not in our modern world. Why should anyone take the time for such a study? 

Packer answers,   

"A fair question! -- but there is, I think, a convincing answer to it. The questioner clearly assumes that a study of the nature and character of God will be impractical and irrelevant for life. In fact, however, it is the most practical project anyone can engage in. Knowing about God is crucially important for the living of our lives. As it would be cruel to an Amazonian tribesman to fly him to London, put him down without explanation in Trafalgar Square and leave him, as one who knew nothing of English or England, to fend for himself, so we are cruel to ourselves if we try to live in this world without knowing about the God whose world it is and who runs it. The world becomes strange, mad, painful a place, and life in it a disappointing and unpleasant business, for those who do not know about God. Disregard the study of God, and you sentence yourself to stumble and blunder through life blindfolded, as it were, with no sense of direction and no understanding of what surrounds you. This way you can waste your life and lose your soul."

(J. I. Packer, Knowing God, pp. 18-19)