BYU sets a fine example, my obsession with white clothing, and a few more hints about the vacation we are taking next week.
If you think that what you wear doesn't matter? Then try coordinating your suitcase delivery to all of your far-flung European lodgings after it misses arriving on the Continent when you did.
Think that you can wear anything and have a great time no matter what? Then wait until you are turned away from holy sights in Indonesia or Israel because of your bare shoulders of exposed knees.
Do you enjoy skipping the first day of sightseeing because you are trying to figure out toiletries, sanitary products, or waiting for your sink-washed underwear to dry? This never has to happen to you again!