A person's head is the position of the head. It has the function of accepting the gas field of Gankun. Black belongs to water and yin. If you wear a hat, it is equivalent to closing a door for the top of the skull, so you can't receive aura.
Hat can not only block the light and wind, but also be a common trend accessory. Most stars in the entertainment circle have the habit of wearing hats, and many people like to wear hats in real life. Solemnly declare: the answer is for reference only, please don't be blindly superstitious.