If you’ve ever found yourself standing in the rain with a collection of flat-pack boxes just too much the wrong shape to get into your car (or perhaps even into Elvis’ car), here’s a suggestion you might like to make to the Ikea’s of this world. Or you could just knuckle under and pay them £80+ to deliver your chipboard….
The store should provide, alongside each cardboard box full of furniture components in the collection shed, an identical cardboard box containing nothing (in fact many of each of these spare boxes could be stored flat, adjacent to the goods themselves and at almost no extra cost).

These empty boxes could be unflattened and carried with ease to your vehicle where you could then undertake a small experiment to see if the antique formica effect fitted kitchen you are about to buy will actually be coming home with you that evening. Even items which are not normally boxed, eg armchairs, could have a rough pop-up cardboard facsimile made for this purpose (or you could just take that home and sit on it, I guess).
This idea also saves our warehouse chums the costs and hassle associated with the ‘immediate returns’ department (who have to cater to people who made it as far as the rainstorm outside only to discover their Shogun Landcruiser inadequately proportioned).
I just found this. Sadly the analysis involved is actually technically ultra difficult
http://un-boxed.blogspot.com/2009/03/krama.html