Modesty, since everyone thinks it’s out of date for some reason.

“Modesty in dress is one of the identifying characteristics of true saints. It is an aid in preserving chastity and an outward sign that the modest person is imbued with humility, decency, and propriety. Immodesty in dress is worldly, excites passions and lusts, places undue emphasis on sex and lewdness, and frequently encourages and invites petting and other immoral practices. It is an outward sign that the immodest person has become hardened to the finer sensitivities of the Spirit and been overcome by a spirit of vanity and pride. Low-necked dresses and those which do not adequately cover the body, for instance, are obviously destructive of decency.

Extremes of dress of any kind are of doubtful propriety. Costly and elaborate clothing in general is anything but indicative that the wearer has overcome the world and is walking humbly before the Lord. On the other hand old-fashioned somber, uniform-type clothing worn by fanatical members of some small religious sects is wholly unbecoming in our modern society. Such habits of dress indicate a lack of understanding of sound and true principles of modesty.”

-Bruce R. McConkie