In the Town of Palm Beach, properties and structures that have historical landmark designations are reviewed by the Landmarks Preservation Commission. They apply the Secretary of Interior Standards for historic preservation, but that can become a subjective process given the individual points of view of those on the board. Any other property in Palm Beach, not landmarked, faces review by the Architectural Review Commission, also known as ARCOM. They have their own criteria for reviewing what comes before them. One of the standards they look at is whether a new structure is excessively similar or dissimilar to other nearby properties and structures. This can lead to some pretty fine lines being drawn and some applicants left designing for the committee, or being denied outright.
Click title for link to a Shiny Sheet article where ARCOM approved a "modern" home, but in the shadow of denying another home with a modern aesthetic months before. That denial was appealed to the Town Council, which upheld the decision. It's good to see them approve a home that breaks from what you usually find on the island, however it came by a split-decision.