Okay, slightly embarassing but...
Since the credit crunch I do nightwork at a local very famous hardware store... totally mind-numbing work, especially for an IT-Manager-by-day. Basically we see the WORST of inefficient deliveries possible.
Generally, each day at least one large truck from EVERY company pulls up (e.g. wood company on Monday, lighting company on Tuesday) to every individual store in the country. They drop off pallets full of boxes of their products. The pallets are moved by forklift by person A into a warehouse. Person B checks it off without opening it and documents it. Sometimes person C is involved in getting it into the right place in the warehouse. During the day, person D checks the stock in the store and person E will determine what stock to put out overnight.
At night, person F will check the stock requests and, usually, person G will use a forklift to deliver pallet to the front of store once it's closed. Then persons H, I, J, K, L and M will randomly open pallets (lots of plastic and carboard) and hand-move the merchandise still in their containing boxes (so not even NEAR a product-box yet) onto ordinary store trolleys. They will then wheel said trolley (containing basically random mixes of stock by now) through the store and then unpack it from its boxes (usually multiple levels of packaging) to get to the bare product. Then they will put it on the shelf. If it doesn't fit on the shelf (about 25% of the time), they place the box on the floor.
Rinse and repeat until about 10-15 pallets (approximately 10-15 tons or more) are emptied in trolley-load batches. Towards the end of the night, persons H, I, J (or possibly K, L, M, depending who gets their stock done first) will go through the store and move (by hand) anything on the floor onto a high shelf out of customers reach. Meanwhile the others are probably moving the extraneous cardboard, plastic, etc. back out to the warehouse and generally shifting stock about.
Then, should stock spaces occur during the day, persons N, O, P will take said stock down (by hand), unpack and put it on the shelf. Very rarely are A-P ever seen by the public.
Now consider that stock can consist of lightbulbs or 40kg worktops, drills or 1.5 tons of tiles, a lightswitch or 200 pieces of timber. The product has a box. The product is boxed (sometimes singly, sometimes with others) by the manufacturer. That is then boxed (sometimes singly, sometimes with others) into larger batches. That is then packed onto pallets and wrapped in plastic. The pallets are then stacked and loaded on a lorry / several lorries. The inefficiency is just rife.
And, yes, we have had four-foot-cube boxes for, say, two lightbulbs, or a lampshade. It's not even unusual. We usually end up at the end of a four-hour night shift (maybe 10-15 pallets of stock) with about 3-4 cubic pallets of cardboard, 1-2 of plastic, and about 0.5 of plastic strapping. That's before you even get into what the product box itself contains (i.e. one lightbulb in a fancy packet).
Now consider the manual effort (and wages) of all those people doing silly tasks like literally hand-loading a trolley from a pallet and wheeling it ten feet, the emissions from the vehicles (forklifts, lorries, etc.), the weight of stuff delivered needlessly, it's just a complete waste.
Though the company in question are now stopping the "overstock" (where stock that is over-ordered is stored over the normal aisles) but only because they've killed people by tumbling stock onto their heads.
I estimate about a 0.1% efficiency in terms of energy used to the "optimal" mathematical solution for getting X tons of stuff from several manufacturers onto a store's shelves.