There are some things about your body that you should know for example: your blood type, things you are allergic to, and your face shape, to name a few. The last one may seem like no big deal, but knowing if your face is oval, square, or round can help you get a more flattering haircut, look more natural when you get fillers, find perfectly fitting glasses, accessories that suits you and makes you look more attractive and neckline in your clothing which looks more appropriate.