Why this obsession with Vanity ?

Why do we shop so much ? why do we strive to look good for parties and gatherings? why do women and nowadays even few men aid themselves with different cosmetics ?   why this obsession with vanity ! As i wonder about these things, i too am a participant in this practice may be i participate in these due to pressure and expectations from my dear ones or due to the pressure of the society in general but i am one of them nevertheless.

As one can see there is a heightened pressure amongst most of us, especially women to look in a certain way, wear newer clothes, not to commit the “sin” of repeating a dress she previously wore in another party and a lot of time is spent on discussing, searching, shopping, trying out different combinations just for the sake of vanity. my sincere question to all of us, is all these worth it ? After all if you google the word Vanity the second  meaning of it is “ the quality of being worthless or futile” .

To make things clear i am not confusing vanity with being fit, being clean and maintaining a decentness in our appearance. I am talking about the extra length we go to please others, try to seek approval of looking beautiful from others which should be avoided, and this culture of getting ready in formal shirts and suits ( esp seen in USA) when attending parties, the irony is in USA people come in shorts for a exec meetings which is very fine with me but get all dressed up to go and dance in a pub, a pub, the primary function of having a party is to relax, why should one dress up so much for relaxing ?

As i grapple with these questions, i am looking forward to a get to gather where every one can attend with casual jeans, un ironed t-shirts, loose hoodies , not so well combed hair and untrimmed beard.