Product design and customer usability are two disciplines that hardly speak to each other, if only within a marketing aspect. In other words, its like engineering something and actually putting it to use in the real world - in the wild - and how it gets adapted and ultimately used and how it breaks down unexpectedly. There's a story of a washing machine company off in Singapore or some shit that sold a particular model way above expectations in some back-county area that hardly even had paved roads, so they went to investigate. Turns out the locals were using this model of clothes washer to wash root vegetables en mass to make their life easier. So they took this and added more rigidity and an actual 'vegetable cycle' to the thing and then made more sales, happy customers, etc.. Not many companies do this, and when they try, it isn't usually too successful since people are typically retarded. I think Ford said something like "if I had listened to my customers, I would have added a second horse" when asked about input on the automobile he made. I know that customer feedback for early iProducts were very negative since people hated having a touchscreen that got smudgy and greasy, hard to see, unusable, etc. They went with it anyways.