In setting up an ArcGIS Hub site (tied to an Open Data Site), when you select two categories, the current filter is an "OR" filter - e.g. "Administration" OR "Public Works" - this results in too many results coming back and so the list is not as useful as if we could filter using and "AND" query - e.g. "Administration" AND" Public Works".
I believe that users expect that as they click more categories, the list will get shorter, not longer.