The real reason

The real reason your brain is so large, Laurel, compared to most of the other blessed creatures dwelling in time and space, is so that you can vividly imagine all the exquisite, exciting, and enthralling details of your heart's desires; not so that you can figure out who you need to meet, when you need to meet them, where you need to be, or how you're going to pull it all together.

Your brain's not nearly that big.

But mine is,
    The Universe

Actually, that's just one of the reasons, Laurel. Some of the other reasons are so that you can take notice of the miracles in your life, feel the joy when you visualize, and, of course, so that you can laugh at yourself whenever you temporarily forget these things. Ha ha.