For example, I often include a calculated dimension that only shows the top 15 items by shipment volume (it could just as easily be the top fifteen salespersons, or top 15 most requested service kits, or whatever). The expression for a calculated dimension like that is:
=If(aggr(rank(sum(SHIPMENTS)),ITEM)<=15,ITEM, 'All Others')
With a chart dimension like that the chart changes as the report user changes the selection. When the selection is Country=FRANCE, for example, the chart shows the top 15 items sold in France, and if the selection is Product=CLOTHING then the chart changes to show the 15 clothing items based on shipment volume. If the report user wants to make a selection for the 15 items then that is as simple as dragging the cursor over the 15 items listed in the chart.
Similar calculated dimensions might look for items with no sales orders or no bill-of-materials or missing pricing data, etc.