The story behind my topic choice

Why do we exactly have a dress code? Every school has the same dress code, no short skirts or shorts, no baggy pants, no tank tops, an so on. I mean i just don't understand why teachers an staff try to inforce this dress code. Nobody ever follows it, So it's a waste of time to even have schools go over it an try to inforce them. Every individual has their own personality. When having your own personality in some people they express it through their clothes. For me i like to wear tank tops. They have it if you straps are to short you can not wear them and that bothers me alot.