Liking your employees to be extremely punctual is pretty objective, but the other two are potentially problematic if you do them wrong.

One example where this comes up a lot is hair. People from backgrounds where straight hair is the norm envision "well-dressed" to include neat and orderly hair, often more neat and more orderly than people with type 3 or 4 hair can actually achieve. So many areas where both straight and curly hair are common have found it necessary to stipulate in law that any grooming expectation you impose has to accommodate the full range of natural hair textures.