About our underclothing; we call them garments. They are not "magic". They are a private, personal reminder of the covenants we make with God in our temples to keep all of His commandments. Some religions wear their signs of faith in clothes that others can see, but we do not. As we keep His commandments we are protected from much of the sorrow in this world.
Garments are also a reminder of how special our bodies are. We view them as temples of God. Garments set a high standard of modesty. They encourage us to treat our bodies with respect which builds self esteem. One young Southern woman related to me what her mother had told her; "If you use your body as bait, don't be surprised if you attract pigs". So true!