most of the people nowadays live for social validation

That is true unfortunately and some are doing things only for this purpose, which is even more sad. What kind of life is that?

sometimes they tell me "you should dress well and elegant to go to work, what will other think"

That is rude and inappropriate. Who the fook they think they are, to tell you to dress up? None of their business, but some people like to poke their nose in other people's business. I usually get rid of these people. Who needs them? I don't.