>other social expectations (like modest hair colours) are also downgraded in importance

The old school "goth" style, well that was breaking the social clothing/makeup etc conventions. Rebelling against the norms. But there would be a group of 5 people doing the exact same thing, rebelling in the same way, and bonding together over it.

I'm not sure to what extent it generalises to the above, but just a thing that was commonly observable