Idk, maybe if you're wearing a suit, but why as a Christian looking to walk with a sound mind and a sound heart, want to be appearing to walk with evil?
It is just vanity, in the end, isn't it? God is going to look at the heart, yes, but I think he would rather the things we show be his holiness and righteousness through our character and our deeds.
Like the child's song:
"This little line of mine,
I'm going to let it shine"
I don't need to be "cool" anymore. I would prefer to be humble and graceful.
I don't want my appearance to be what teaches people, because it would distract from what God has done in my life.
As Jesus said himself, "First clean the inside of the cup and dish, and then the outside also will be clean."