Last-mile delivery.

The final hop, from the delivery unit that serves a postcode to the actual address. Line-haul is cheap per parcel because thousands of them ride in one trailer; the last mile is one van, one stop, one address, with no density to spread the cost across. Cost follows density, so the leg that has none is the expensive one, and most of parcel economics is aimed squarely at it: lockers, pickup points, delivery windows, and consolidating two parcels into one stop. A POD order is the worst-shaped freight for all of that, a single item to a residential address with nothing to consolidate against, a residential surcharge, and a re-attempt if nobody is home. Shops meet it as the gap between the tidy zone-based rate they quoted at checkout and the invoice that arrives with accessorials on it.